diff --git a/source/source_base/math_chebyshev.cpp b/source/source_base/math_chebyshev.cpp
index aaa0e82b74..8a84686ea5 100644
--- a/source/source_base/math_chebyshev.cpp
+++ b/source/source_base/math_chebyshev.cpp
@@ -417,7 +417,7 @@ void Chebyshev<REAL, Device>::calfinalvec_real(
     std::complex<REAL>* arrayn = nullptr;
     std::complex<REAL>* arrayn_1 = nullptr;
     assert(N >= 0 && LDA >= N);
-    int ndmxt;
+    int ndmxt = 0;
     if (m == 1)
     {
         ndmxt = N * m;
@@ -486,7 +486,7 @@ void Chebyshev<REAL, Device>::calfinalvec_complex(
     std::complex<REAL>* arrayn = nullptr;
     std::complex<REAL>* arrayn_1 = nullptr;
     assert(N >= 0 && LDA >= N);
-    int ndmxt;
+    int ndmxt = 0;
     if (m == 1)
     {
         ndmxt = N * m;
@@ -585,7 +585,7 @@ void Chebyshev<REAL, Device>::tracepolyA(
     std::complex<REAL>* arrayn = nullptr;
     std::complex<REAL>* arrayn_1 = nullptr;
     assert(N >= 0 && LDA >= N);
-    int ndmxt;
+    int ndmxt = 0;
     if (m == 1)
     {
         ndmxt = N * m;
diff --git a/source/source_base/math_erf_complex.cpp b/source/source_base/math_erf_complex.cpp
index 18709c4866..4c7385245a 100644
--- a/source/source_base/math_erf_complex.cpp
+++ b/source/source_base/math_erf_complex.cpp
@@ -106,7 +106,7 @@ std::complex<double> ErrorFunc::scaled_w(std::complex<double> z, double relerr)
     else if (x < 10)
     {
         double prod2ax = 1, prodm2ax = 1;
-        double expx2;
+        double expx2 = 0.0;
 
         if (std::isnan(y))
             return std::complex<double>(y, y);
@@ -235,7 +235,7 @@ std::complex<double> ErrorFunc::scaled_w(std::complex<double> z, double relerr)
         sum3 = std::exp(-dx * dx) / (a2 * (n0 * n0) + y * y);
         sum5 = a * n0 * sum3;
         double exp1 = std::exp(4 * a * dx), exp1dn = 1;
-        int dn;
+        int dn = 0;
         for (dn = 1; n0 - dn > 0; ++dn)
         { // loop over n0-dn and n0+dn terms
             double np = n0 + dn, nm = n0 - dn;
diff --git a/source/source_base/math_ylmreal.cpp b/source/source_base/math_ylmreal.cpp
index 3a11f95438..e94b027bb3 100644
--- a/source/source_base/math_ylmreal.cpp
+++ b/source/source_base/math_ylmreal.cpp
@@ -179,7 +179,7 @@ void YlmReal::rlylm
 				{
 					int twok = 2 * ik;
 				
-					double gamma;
+					double gamma = 0.0;
 					double aux0, aux1, aux2, aux3;
 				
 					aux0 = pow(-1.0, ik) * pow(2.0, -il);
diff --git a/source/source_base/tool_check.cpp b/source/source_base/tool_check.cpp
index a9450b4fcb..dab7dd5f21 100644
--- a/source/source_base/tool_check.cpp
+++ b/source/source_base/tool_check.cpp
@@ -49,7 +49,7 @@ void CHECK_INT(std::ifstream &ifs,const int &v,bool quit)
 void CHECK_DOUBLE(std::ifstream &ifs,const double &v,bool quit)
 {
 	const double tiny = 1.0e-5;
-	double v_in;
+	double v_in = 0.0;
 	ifs >> v_in;
 	if( fabs(v - v_in) > tiny )
 	{
diff --git a/source/source_base/tool_quit.cpp b/source/source_base/tool_quit.cpp
index 77c855c7a0..efd72278cc 100644
--- a/source/source_base/tool_quit.cpp
+++ b/source/source_base/tool_quit.cpp
@@ -65,7 +65,7 @@ void WARNING_QUIT(const std::string &file,const std::string &description)
 
 	#ifdef __MPI /* if it is MPI run, finalize first, then exit */
 	std::cout << "Detecting if MPI has been initialized..." << std::endl;
-	int is_initialized;
+	int is_initialized = 0;
     MPI_Initialized(&is_initialized);
 	if (is_initialized) {
 		std::cout << "Terminating ABACUS with multiprocessing environment." << std::endl;
diff --git a/source/source_base/ylm.cpp b/source/source_base/ylm.cpp
index cd7336718d..b055ed37ad 100644
--- a/source/source_base/ylm.cpp
+++ b/source/source_base/ylm.cpp
@@ -474,7 +474,7 @@ void Ylm::rlylm
 				{
 					int twok = 2 * ik;
 
-					double gamma;
+					double gamma = 0.0;
 					double aux0, aux1, aux2, aux3;
 
 					aux0 = pow(-1.0, ik) * pow(2.0, -il);
@@ -1107,7 +1107,7 @@ void Ylm::hes_rl_sph_harm
 	hrly.resize( (Lmax+1)*(Lmax+1), std::vector<double>(6) );
 
 	double radius2 = x*x+y*y+z*z;
-	double coeff;
+	double coeff = 0.0;
 
 	//begin calculation
 	/***************************
@@ -1867,7 +1867,7 @@ void Ylm::rlylm
 				{
 					int twok = 2 * ik;
 
-					double gamma;
+					double gamma = 0.0;
 					double aux0, aux1, aux2, aux3;
 
 					aux0 = pow(-1.0, ik) * pow(2.0, -il);
diff --git a/source/source_cell/klist.cpp b/source/source_cell/klist.cpp
index b9ee8c4eba..1bba575528 100644
--- a/source/source_cell/klist.cpp
+++ b/source/source_cell/klist.cpp
@@ -466,7 +466,7 @@ void K_Vectors::interpolate_k_between(std::ifstream& ifk, std::vector<ModuleBase
 
 double K_Vectors::Monkhorst_Pack_formula(const int& k_type, const double& offset, const int& n, const int& dim)
 {
-    double coordinate;
+    double coordinate = 0.0;
     if (k_type == 1)
     {
         coordinate = (offset + 2.0 * (double)n - (double)dim - 1.0) / (2.0 * (double)dim);
diff --git a/source/source_cell/read_pp_blps.cpp b/source/source_cell/read_pp_blps.cpp
index 682f39dfdc..5370dbc41b 100644
--- a/source/source_cell/read_pp_blps.cpp
+++ b/source/source_cell/read_pp_blps.cpp
@@ -24,8 +24,8 @@ int Pseudopot_upf::read_pseudo_blps(std::ifstream &ifs, Atom_pseudo& pp)
     // if(!SCAN_BEGIN(ifs,"BLPS")) WARNING_QUIT("read_pp_blps","Find no PP_HEADER");
     ifs.ignore(300, '\n');
 
-    double zatom;
-    double zion;
+    double zatom = 0.0;
+    double zion = 0.0;
     ifs >> zatom >> zion;
     pp.zv = zion;
     ifs.ignore(300, '\n');
diff --git a/source/source_cell/read_pp_upf100.cpp b/source/source_cell/read_pp_upf100.cpp
index 0e91dffccc..9327ebe712 100644
--- a/source/source_cell/read_pp_upf100.cpp
+++ b/source/source_cell/read_pp_upf100.cpp
@@ -326,7 +326,7 @@ void Pseudopot_upf::read_pseudo_nl(std::ifstream& ifs, Atom_pseudo& pp)
         ModuleBase::GlobalFunc::READ_VALUE(ifs, this->nd); // nl_4
         for (int i = 0; i < this->nd; i++)
         {
-            double swap;
+            double swap = 0.0;
             ifs >> nb >> mb >> swap;
             nb--;
             mb--;
diff --git a/source/source_cell/read_pp_upf201.cpp b/source/source_cell/read_pp_upf201.cpp
index e0941664bf..d02bb8e6d5 100644
--- a/source/source_cell/read_pp_upf201.cpp
+++ b/source/source_cell/read_pp_upf201.cpp
@@ -807,7 +807,7 @@ void Pseudopot_upf::read_pseudo_upf201_fullwfc(std::ifstream& ifs)
     std::string word;
     std::string name[50];
     std::string val[50];
-    int nparameter;
+    int nparameter = 0;
     this->aewfc.create(this->nbeta, this->mesh);
     this->pswfc.create(this->nbeta, this->mesh);
     ModuleBase::GlobalFunc::SCAN_BEGIN(ifs, "<PP_FULL_WFC");
diff --git a/source/source_cell/setup_nonlocal.cpp b/source/source_cell/setup_nonlocal.cpp
index 74911595b6..96bf898864 100644
--- a/source/source_cell/setup_nonlocal.cpp
+++ b/source/source_cell/setup_nonlocal.cpp
@@ -312,7 +312,7 @@ void InfoNonlocal::Read_NonLocal(const int& it,
         {
             if (ModuleBase::GlobalFunc::SCAN_BEGIN(ifs, "<PP_BETA>", false))
             {
-                int iproj;
+                int iproj = 0;
                 ModuleBase::GlobalFunc::READ_VALUE(ifs, iproj);
                 if (iproj != p1)
                 {
diff --git a/source/source_estate/cal_ux.cpp b/source/source_estate/cal_ux.cpp
index 5175e48d5a..f7ea856386 100644
--- a/source/source_estate/cal_ux.cpp
+++ b/source/source_estate/cal_ux.cpp
@@ -93,7 +93,7 @@ void cal_ux(UnitCell& ucell) {
 
 bool judge_parallel(double a[3], ModuleBase::Vector3<double> b) {
     bool jp = false;
-    double cross;
+    double cross = 0.0;
     cross = pow((a[1] * b.z - a[2] * b.y), 2)
             + pow((a[2] * b.x - a[0] * b.z), 2)
             + pow((a[0] * b.y - a[1] * b.x), 2);
diff --git a/source/source_hamilt/module_vdw/vdwd2_parameters.cpp b/source/source_hamilt/module_vdw/vdwd2_parameters.cpp
index a562244be3..3ac48e1819 100644
--- a/source/source_hamilt/module_vdw/vdwd2_parameters.cpp
+++ b/source/source_hamilt/module_vdw/vdwd2_parameters.cpp
@@ -50,7 +50,7 @@ void Vdwd2Parameters::C6_input(const std::string &file, const std::string &unit)
             ModuleBase::WARNING_QUIT("Vdwd2::C6_input",
                                      "Can not find the file " + ModuleBase::GlobalFunc::TO_STRING(file));
         std::string element;
-        double value;
+        double value = 0.0;
         while (ifs >> element >> value)
             C6_[element] = value;
         ifs.close();
@@ -77,7 +77,7 @@ void Vdwd2Parameters::R0_input(const std::string &file, const std::string &unit)
             ModuleBase::WARNING_QUIT("Vdwd2::R0_input",
                                      "Can not find the file " + ModuleBase::GlobalFunc::TO_STRING(file));
         std::string element;
-        double value;
+        double value = 0.0;
         while (ifs >> element >> value)
             R0_[element] = value;
         ifs.close();
diff --git a/source/source_hamilt/module_vdw/vdwd3.cpp b/source/source_hamilt/module_vdw/vdwd3.cpp
index 95aeac8226..66245e0f09 100644
--- a/source/source_hamilt/module_vdw/vdwd3.cpp
+++ b/source/source_hamilt/module_vdw/vdwd3.cpp
@@ -88,7 +88,7 @@ void Vdwd3::cal_energy()
     ModuleBase::timer::tick("Vdwd3", "cal_energy");
     init();
 
-    int ij;
+    int ij = 0;
     double c6 = 0.0, c8 = 0.0, r2 = 0.0, r6 = 0.0, r8 = 0.0, rr = 0.0, damp6 = 0.0, damp8 = 0.0;
     double e6 = 0.0, e8 = 0.0, eabc = 0.0;
     std::vector<double> cc6ab(ucell_.nat * ucell_.nat), cn(ucell_.nat);
@@ -96,7 +96,7 @@ void Vdwd3::cal_energy()
     ModuleBase::Vector3<double> tau;
     if (para_.version() == "d3_0") // DFT-D3(zero-damping)
     {
-        double tmp;
+        double tmp = 0.0;
         for (int iat = 0; iat != ucell_.nat - 1; iat++) {
             for (int jat = iat + 1; jat != ucell_.nat; jat++)
             {
@@ -178,7 +178,7 @@ void Vdwd3::cal_energy()
     } // end d3_0
     else if (para_.version() == "d3_bj") // DFT-D3(BJ-damping)
     {
-        double r42;
+        double r42 = 0.0;
         for (int iat = 0; iat != ucell_.nat; iat++)
         {
             for (int jat = iat + 1; jat != ucell_.nat; jat++)
@@ -860,7 +860,7 @@ void Vdwd3::pbc_gdisp(std::vector<ModuleBase::Vector3<double>> &g, ModuleBase::m
     } // end d3_0
     else if (para_.version() == "d3_bj")
     {
-        double r4;
+        double r4 = 0.0;
         for (int iat = 0; iat != ucell_.nat; iat++)
         {
             get_dc6_dcnij(para_.mxc()[iz_[iat]], para_.mxc()[iz_[iat]], cn[iat], cn[iat],
diff --git a/source/source_hamilt/module_xc/xc_funct_corr_gga.cpp b/source/source_hamilt/module_xc/xc_funct_corr_gga.cpp
index 2c94989482..3c88eb653c 100644
--- a/source/source_hamilt/module_xc/xc_funct_corr_gga.cpp
+++ b/source/source_hamilt/module_xc/xc_funct_corr_gga.cpp
@@ -104,7 +104,7 @@ void XC_Functional::ggac(const double &rho,const double &grho, double &sc, doubl
     y = af * t * t;
     xy = (1.0 + y) / (1.0 + y + y * y);
 
-    double x;
+    double x = 0.0;
     x = 1.0 + y + y * y;
     qy = y * y * (2.0 + y) / (x * x);
     s1 = 1.0 + 2.0 * al / be * t * t * xy;
diff --git a/source/source_hamilt/module_xc/xc_funct_corr_lda.cpp b/source/source_hamilt/module_xc/xc_funct_corr_lda.cpp
index 4a749320b8..5b6ff5367b 100644
--- a/source/source_hamilt/module_xc/xc_funct_corr_lda.cpp
+++ b/source/source_hamilt/module_xc/xc_funct_corr_lda.cpp
@@ -138,7 +138,7 @@ void XC_Functional::vwn(const double &rs, double &ec, double &vc)
     fx = rs + b * rs12 + c;
     qx = atan(q / (2.0 * rs12 + b));
 
-    double x;
+    double x = 0.0;
     x = (rs12 - x0);
     ec = a * (log(rs / fx) + f1 * qx - f2 * (log((x * x) /
               fx) + f3 * qx));
diff --git a/source/source_hamilt/module_xc/xc_functional_gradcorr.cpp b/source/source_hamilt/module_xc/xc_functional_gradcorr.cpp
index 66b0a4a0d6..008109377c 100644
--- a/source/source_hamilt/module_xc/xc_functional_gradcorr.cpp
+++ b/source/source_hamilt/module_xc/xc_functional_gradcorr.cpp
@@ -226,7 +226,7 @@ void XC_Functional::gradcorr(double &etxc, double &vtxc, ModuleBase::matrix &v,
 
 	if(nspin0==1)
 	{
-		double segno;
+		double segno = 0.0;
 #ifdef _OPENMP
 #pragma omp for
 #endif
@@ -249,7 +249,7 @@ void XC_Functional::gradcorr(double &etxc, double &vtxc, ModuleBase::matrix &v,
 #ifdef USE_LIBXC
 					if(func_type == 3 || func_type == 5) //the gradcorr part to stress of mGGA
 					{
-						double v3xc;
+						double v3xc = 0.0;
 						double atau = chr->kin_r[0][ir]/2.0;
 						XC_Functional_Libxc::tau_xc( func_id, arho, grho2a, atau, sxc, v1xc, v2xc, v3xc);
 					}
diff --git a/source/source_hamilt/module_xc/xc_functional_wrapper_gcxc.cpp b/source/source_hamilt/module_xc/xc_functional_wrapper_gcxc.cpp
index ea6a5a3e1e..3956d29702 100644
--- a/source/source_hamilt/module_xc/xc_functional_wrapper_gcxc.cpp
+++ b/source/source_hamilt/module_xc/xc_functional_wrapper_gcxc.cpp
@@ -128,7 +128,7 @@ void XC_Functional::gcx_spin(double rhoup, double rhodw, double grhoup2, double
     // parameter :
     double small = 1.e-10;
     double sxup, sxdw;
-    int iflag;
+    int iflag = 0;
 
     // exchange
     double rho = rhoup + rhodw;
@@ -247,7 +247,7 @@ void XC_Functional::gcc_spin(double rho, double &zeta, double grho, double &sc,
     double small = 1.0e-10;
 	double epsr = 1.0e-6;
 
-    double x;
+    double x = 0.0;
 
     sc = 0.00;
     v1cup = 0.00; v1cdw = 0.00;
diff --git a/source/source_hamilt/module_xc/xc_functional_wrapper_xc.cpp b/source/source_hamilt/module_xc/xc_functional_wrapper_xc.cpp
index d13eb0d129..0a9bffbc42 100644
--- a/source/source_hamilt/module_xc/xc_functional_wrapper_xc.cpp
+++ b/source/source_hamilt/module_xc/xc_functional_wrapper_xc.cpp
@@ -17,7 +17,7 @@ void XC_Functional::xc(const double &rho, double &exc, double &vxc)
 
 	double third = 1.0 / 3.0;
 	double pi34 = 0.6203504908994e0 ; // pi34=(3/4pi)^(1/3)
-	double rs;
+	double rs = 0.0;
     double e,v;
     
     exc = vxc = 0.00;
diff --git a/source/source_hsolver/diago_elpa_native.cpp b/source/source_hsolver/diago_elpa_native.cpp
index f320191d28..dc4bf2b6d7 100644
--- a/source/source_hsolver/diago_elpa_native.cpp
+++ b/source/source_hsolver/diago_elpa_native.cpp
@@ -77,7 +77,7 @@ void DiagoElpaNative<T>::diag_pool(hamilt::MatrixBlock<T>& h_mat,
     }
 
     // elpa_init(20210430);
-    int success;
+    int success = 0;
     elpa_t handle = elpa_allocate(&success);
 #ifdef _OPENMP
     int num_threads = omp_get_max_threads();
diff --git a/source/source_hsolver/hsolver_pw.cpp b/source/source_hsolver/hsolver_pw.cpp
index 7d178f699b..2ea7b92a2b 100644
--- a/source/source_hsolver/hsolver_pw.cpp
+++ b/source/source_hsolver/hsolver_pw.cpp
@@ -544,8 +544,8 @@ void HSolverPW<T, Device>::build_k_neighbors() {
     // Store k-points and corresponding indices
     struct KPoint {
         ModuleBase::Vector3<double> kvec;
-        int index;
-        double norm;
+        int index = 0;
+        double norm = 0.0;
 
         KPoint(const ModuleBase::Vector3<double>& v, int i) :
             kvec(v), index(i), norm(v.norm()) {}
diff --git a/source/source_hsolver/module_genelpa/elpa_new.cpp b/source/source_hsolver/module_genelpa/elpa_new.cpp
index 3d214d20fd..d045482190 100644
--- a/source/source_hsolver/module_genelpa/elpa_new.cpp
+++ b/source/source_hsolver/module_genelpa/elpa_new.cpp
@@ -57,7 +57,7 @@ ELPA_Solver::ELPA_Solver(const bool isReal,
     else
         kernel_id = read_complex_kernel();
     // cout<<"kernel id is inited as "<<kernel_id<<"\n";
-    int error;
+    int error = 0;
 
     static int total_handle = 0;
 
@@ -139,7 +139,7 @@ ELPA_Solver::ELPA_Solver(const bool isReal,
 
     int error;
     static std::map<int, elpa_t> NEW_ELPA_HANDLE_POOL;
-    static int total_handle;
+    static int total_handle = 0;
 
 #ifdef _OPENMP
     int num_threads = omp_get_max_threads();
@@ -270,7 +270,7 @@ int ELPA_Solver::read_cpuflag()
 
 int ELPA_Solver::read_real_kernel()
 {
-    int kernel_id;
+    int kernel_id = 0;
 
     if (const char* env = getenv("ELPA_DEFAULT_real_kernel"))
     {
@@ -454,7 +454,7 @@ int ELPA_Solver::read_complex_kernel()
 int ELPA_Solver::allocate_work()
 {
     unsigned long nloc = static_cast<unsigned long>(narows) * nacols; // local size
-    unsigned long maxloc; // maximum local size
+    unsigned long maxloc = 0; // maximum local size
     MPI_Allreduce(&nloc, &maxloc, 1, MPI_UNSIGNED_LONG, MPI_MAX, comm);
     maxloc = nloc;
 
@@ -467,7 +467,7 @@ int ELPA_Solver::allocate_work()
 
 void ELPA_Solver::timer(int myid, const char function[], const char step[], double& t0)
 {
-    double t1;
+    double t1 = 0.0;
     if (t0 < 0) // t0 < 0 means this is the init call before the function
     {
         t0 = MPI_Wtime();
diff --git a/source/source_hsolver/module_genelpa/elpa_new_complex.cpp b/source/source_hsolver/module_genelpa/elpa_new_complex.cpp
index 0c78009522..cf28835942 100644
--- a/source/source_hsolver/module_genelpa/elpa_new_complex.cpp
+++ b/source/source_hsolver/module_genelpa/elpa_new_complex.cpp
@@ -19,9 +19,9 @@ extern std::map<int, elpa_t> NEW_ELPA_HANDLE_POOL;
 
 int ELPA_Solver::eigenvector(std::complex<double>* A, double* EigenValue, std::complex<double>* EigenVector)
 {
-    int info;
-    int allinfo;
-    double t;
+    int info = 0;
+    int allinfo = 0;
+    double t = 0.0;
 
     if((loglevel>0 && myid==0) || loglevel>1)
     {
@@ -42,7 +42,7 @@ int ELPA_Solver::generalized_eigenvector(std::complex<double>* A, std::complex<d
                                          double* EigenValue, std::complex<double>* EigenVector)
 {
     int info, allinfo;
-    double t;
+    double t = 0.0;
 
     if((loglevel>0 && myid==0) || loglevel>1)
     {
@@ -164,7 +164,7 @@ int ELPA_Solver::decomposeRightMatrix(std::complex<double>* B, double* EigenValu
 {
     int info=0;
     int allinfo=0;
-    double t;
+    double t = 0.0;
 
     // first try cholesky decomposing
     if(nFull<CHOLESKY_CRITICAL_SIZE) // use pdpotrf for small matrix
@@ -316,7 +316,7 @@ int ELPA_Solver::decomposeRightMatrix(std::complex<double>* B, double* EigenValu
 
 int ELPA_Solver::composeEigenVector(int DecomposedState, std::complex<double>* B, std::complex<double>* EigenVector)
 {
-    double t;
+    double t = 0.0;
     if(DecomposedState==1 || DecomposedState==2)
     {
         // transform the eigenvectors to original general equation, let U^-1*q, and put to q
diff --git a/source/source_hsolver/module_genelpa/elpa_new_real.cpp b/source/source_hsolver/module_genelpa/elpa_new_real.cpp
index a780c89f55..cc6d0242bd 100644
--- a/source/source_hsolver/module_genelpa/elpa_new_real.cpp
+++ b/source/source_hsolver/module_genelpa/elpa_new_real.cpp
@@ -18,8 +18,8 @@ extern std::map<int, elpa_t> NEW_ELPA_HANDLE_POOL;
 
 int ELPA_Solver::eigenvector(double* A, double* EigenValue, double* EigenVector)
 {
-    int info;
-    double t;
+    int info = 0;
+    double t = 0.0;
 
     if (loglevel > 0 && myid == 0)
     {
@@ -41,7 +41,7 @@ int ELPA_Solver::generalized_eigenvector(double* A,
                                          double* EigenVector)
 {
     int info, allinfo;
-    double t;
+    double t = 0.0;
 
     if (loglevel > 0 && myid == 0)
     {
@@ -407,7 +407,7 @@ void ELPA_Solver::verify(double* A, double* EigenValue, double* EigenVector, dou
     maxError = 0;
     for (int i = 1; i <= nev; ++i)
     {
-        double E;
+        double E = 0.0;
         ScalapackConnector::dot(nFull, E, R, 1, i, 1, R, 1, i, 1, desc);
         // printf("myid: %d, i: %d, E: %lf\n", myid, i, E);
         sumError += E;
diff --git a/source/source_hsolver/module_genelpa/utils.cpp b/source/source_hsolver/module_genelpa/utils.cpp
index d9e6e74c59..6654c33b9e 100644
--- a/source/source_hsolver/module_genelpa/utils.cpp
+++ b/source/source_hsolver/module_genelpa/utils.cpp
@@ -25,7 +25,7 @@ void initBlacsGrid(int loglevel,
     int nprows, npcols;
     int myprow, mypcol;
     int nprocs, myid;
-    int info;
+    int info = 0;
     MPI_Comm_size(comm, &nprocs);
     MPI_Comm_rank(comm, &myid);
     // set blacs parameters
@@ -137,7 +137,7 @@ void loadMatrix(const char FileName[], int nFull, double* a, int* desca, int bla
 void saveLocalMatrix(const char filePrefix[], int narows, int nacols, double* a)
 {
     char FileName[80];
-    int myid;
+    int myid = 0;
     std::ofstream matrixFile;
 #ifdef __MPI
     MPI_Comm_rank(MPI_COMM_WORLD, &myid);
diff --git a/source/source_hsolver/module_pexsi/dist_bcd_matrix.cpp b/source/source_hsolver/module_pexsi/dist_bcd_matrix.cpp
index ff3f85f32b..93a6dcb5b0 100644
--- a/source/source_hsolver/module_pexsi/dist_bcd_matrix.cpp
+++ b/source/source_hsolver/module_pexsi/dist_bcd_matrix.cpp
@@ -48,7 +48,7 @@ DistBCDMatrix::DistBCDMatrix(MPI_Comm comm,
     }
 
     // synchronize matrix parameters to all processes, including those are not in bcd group
-    int myid_in_comm_world;
+    int myid_in_comm_world = 0;
     MPI_Comm_rank(MPI_COMM_WORLD, &myid_in_comm_world);
     if (myid_in_comm_world == 0)
     {
diff --git a/source/source_hsolver/module_pexsi/dist_ccs_matrix.cpp b/source/source_hsolver/module_pexsi/dist_ccs_matrix.cpp
index 74391f2fbe..0a73653c8e 100644
--- a/source/source_hsolver/module_pexsi/dist_ccs_matrix.cpp
+++ b/source/source_hsolver/module_pexsi/dist_ccs_matrix.cpp
@@ -55,7 +55,7 @@ DistCCSMatrix::DistCCSMatrix(MPI_Comm comm_in, int nproc_data_in, int size_in)
     this->size = size_in;
     this->nnz = 0;
     this->nnzLocal = 0;
-    int myproc;
+    int myproc = 0;
     if (comm != MPI_COMM_NULL)
     {
         MPI_Comm_size(comm, &nprocs);
diff --git a/source/source_hsolver/module_pexsi/dist_matrix_transformer.cpp b/source/source_hsolver/module_pexsi/dist_matrix_transformer.cpp
index 313a840e68..7a4ecec6b1 100644
--- a/source/source_hsolver/module_pexsi/dist_matrix_transformer.cpp
+++ b/source/source_hsolver/module_pexsi/dist_matrix_transformer.cpp
@@ -28,8 +28,8 @@ inline int DistMatrixTransformer::MinimumIndexPosition(const bool isFirst,
 {
     // usually the minimum index is continuous, so it will be a good idea to
     // check the one next to the previous index first.
-    static int pre_position; // previous position in index array of minimum index,
-    static int pre_process;  // the process contains previous index
+    static int pre_position = 0; // previous position in index array of minimum index,
+    static int pre_process = 0;  // the process contains previous index
 
     int minimum_index
         = INT_MAX; // the minimum index, initial value is a large number which is larger than any other index;
@@ -110,7 +110,7 @@ inline void DistMatrixTransformer::buildCCSParameter(const int size,
 
     int pre_col = -1;
     int nnz_now = 0;
-    int p_mini;
+    int p_mini = 0;
     p_mini = MinimumIndexPosition(true, nprocs, &size_process[0], &displacement_process[0], position_index);
     while (p_mini >= 0)
     {
@@ -146,7 +146,7 @@ inline void DistMatrixTransformer::countMatrixDistribution(int N, double* A, std
 {
     for (int i = 0; i < N; ++i)
     {
-        int key;
+        int key = 0;
         if (fabs(A[i] < 1e-31))
             key = -100;
         else
diff --git a/source/source_hsolver/module_pexsi/simple_pexsi.cpp b/source/source_hsolver/module_pexsi/simple_pexsi.cpp
index edf000ecae..255b1019b3 100644
--- a/source/source_hsolver/module_pexsi/simple_pexsi.cpp
+++ b/source/source_hsolver/module_pexsi/simple_pexsi.cpp
@@ -27,7 +27,7 @@ namespace pexsi
 {
 inline void strtolower(char* sa, char* sb)
 {
-    char c;
+    char c = '\0';
     int len = strlen(sa);
     for (int i = 0; i < len; i++)
     {
@@ -172,8 +172,8 @@ void splitNProc2NProwNPcol(const int NPROC, int& nprow, int& npcol)
     }
     else
     {
-        int flag;
-        int i;
+        int flag = 0;
+        int i = 0;
         int low = pow(integral_part, 2);
         int high = pow(integral_part + 1, 2);
         if ((NPROC - low) >= (high - NPROC))
@@ -218,7 +218,7 @@ int simplePEXSI(MPI_Comm comm_PEXSI,
 
     if (comm_2D == MPI_COMM_NULL && comm_PEXSI == MPI_COMM_NULL)
         return 0;
-    int myid;
+    int myid = 0;
     std::ofstream f_log;
     if (comm_PEXSI != MPI_COMM_NULL)
     {
@@ -228,15 +228,15 @@ int simplePEXSI(MPI_Comm comm_PEXSI,
     //  set up PEXSI parameter
     PPEXSIOptions options;
     PPEXSISetDefaultOptions(&options);
-    int numProcessPerPole;
-    double ZERO_Limit;
+    int numProcessPerPole = 0;
+    double ZERO_Limit = 0.0;
     loadPEXSIOption(comm_PEXSI, PexsiOptionFile, options, numProcessPerPole, ZERO_Limit);
     options.mu0 = mu0;
 
     ModuleBase::timer::tick("Diago_LCAO_Matrix", "setup_PEXSI_plan");
     PPEXSIPlan plan;
-    int info;
-    int outputFileIndex;
+    int info = 0;
+    int outputFileIndex = 0;
     int pexsi_prow, pexsi_pcol;
     ModuleBase::timer::tick("Diago_LCAO_Matrix", "splitNProc2NProwNPcol");
     splitNProc2NProwNPcol(numProcessPerPole, pexsi_prow, pexsi_pcol);
@@ -292,11 +292,11 @@ int simplePEXSI(MPI_Comm comm_PEXSI,
                                SnzvalLocal,
                                &info);
 
-        double nelec;
-        double muMinInertia;
-        double muMaxInertia;
-        int numTotalPEXSIIter;
-        int numTotalInertiaIter; // Number of total inertia[out]
+        double nelec = 0.0;
+        double muMinInertia = 0.0;
+        double muMaxInertia = 0.0;
+        int numTotalPEXSIIter = 0;
+        int numTotalInertiaIter = 0; // Number of total inertia[out]
         // LiuXh modify 2021-04-29, add DONE(ofs_running,"xx") for test
         ModuleBase::timer::tick("Diago_LCAO_Matrix", "PEXSIDFT");
         PPEXSIDFTDriver2(plan,                 // PEXSI plan[in]
diff --git a/source/source_io/bessel_basis.cpp b/source/source_io/bessel_basis.cpp
index 5768f411e0..2795fefa25 100644
--- a/source/source_io/bessel_basis.cpp
+++ b/source/source_io/bessel_basis.cpp
@@ -392,10 +392,10 @@ void Bessel_Basis::readin_C4(
 
 					if(ModuleBase::GlobalFunc::SCAN_BEGIN(inc4, "<INPUTS>"))
 					{
-						double tmp_ecut;
-						double tmp_rcut;
-						double tmp_enumber;
-						double tmp_tolerence;
+						double tmp_ecut = 0.0;
+						double tmp_rcut = 0.0;
+						double tmp_enumber = 0.0;
+						double tmp_tolerence = 0.0;
 						ModuleBase::GlobalFunc::READ_VALUE( inc4, tmp_ecut);
 						ModuleBase::GlobalFunc::READ_VALUE( inc4, tmp_rcut);
 						ModuleBase::GlobalFunc::READ_VALUE( inc4, tmp_enumber);
diff --git a/source/source_io/cif_io.cpp b/source/source_io/cif_io.cpp
index c06ecb7033..a03cd0d15c 100644
--- a/source/source_io/cif_io.cpp
+++ b/source/source_io/cif_io.cpp
@@ -238,7 +238,7 @@ void bcast_cifmap(std::map<std::string, std::vector<std::string>>& map, // the m
                   const int rank = 0)   // source rank: from which rank to broadcast
 {
 #ifdef __MPI
-    int myrank;
+    int myrank = 0;
     MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
     // use Parallel_Common namespace bcast_int and bcast_string to broadcast the size of map and key, value pairs
     int size = map.size();
@@ -328,7 +328,7 @@ void ModuleIO::CifParser::write(const std::string& fcif,
                                 const std::string& cell_formula_units_z)
 {
 #ifdef __MPI // well...very simple...
-    int myrank;
+    int myrank = 0;
     MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
     if (myrank != rank) // if present rank is not the rank assigned to write the cif file, then return
     {
@@ -402,7 +402,7 @@ void ModuleIO::CifParser::write(const std::string& fcif,
                                 const std::string& cell_formula_units_z)
 {
 #ifdef __MPI
-    int myrank;
+    int myrank = 0;
     MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
     if (myrank != rank) // if present rank is not the rank assigned to write the cif file, then return
     {
@@ -429,7 +429,7 @@ void ModuleIO::CifParser::write(const std::string& fcif,
                                 const int rank)
 {
 #ifdef __MPI
-    int myrank;
+    int myrank = 0;
     MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
     if (myrank != rank)  // if present rank is not the rank assigned to write the cif file, then return
     {
@@ -437,7 +437,7 @@ void ModuleIO::CifParser::write(const std::string& fcif,
     }
 #endif
     std::vector<double> veca, vecb, vecc;
-    int natom;
+    int natom = 0;
     std::vector<std::string> atom_site_labels;
     std::vector<double> atom_site_fract_coords;
     _unpack_ucell(ucell, veca, vecb, vecc, natom, atom_site_labels, atom_site_fract_coords);
@@ -468,7 +468,7 @@ void ModuleIO::CifParser::read(const std::string& fcif,
     // okey for read, cannot just use if rank != 0 then return, because need to broadcast the map
     out.clear();
 #ifdef __MPI
-    int myrank;
+    int myrank = 0;
     MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
     if (myrank == rank) // only the rank assigned to read the cif file will read the file
     {
diff --git a/source/source_io/csr_reader.cpp b/source/source_io/csr_reader.cpp
index 160cb78a61..7e85c137b6 100644
--- a/source/source_io/csr_reader.cpp
+++ b/source/source_io/csr_reader.cpp
@@ -40,7 +40,7 @@ void csrFileReader<T>::parseFile()
     for (int i = 0; i < numberOfR; i++)
     {
         std::vector<int> RCoord(3);
-        int nonZero;
+        int nonZero = 0;
 
         readLine();
         ss >> RCoord[0] >> RCoord[1] >> RCoord[2] >> nonZero;
diff --git a/source/source_io/get_pchg_lcao.cpp b/source/source_io/get_pchg_lcao.cpp
index 346b56f12a..82de5db224 100644
--- a/source/source_io/get_pchg_lcao.cpp
+++ b/source/source_io/get_pchg_lcao.cpp
@@ -408,7 +408,7 @@ void Get_pchg_lcao::idmatrix(const int& ib,
 
         if (ib_local >= 0)
         {
-            double wg_value;
+            double wg_value = 0.0;
             if (if_separate_k)
             {
                 wg_value = (ib < fermi_band) ? wg_sum_k : wg_sum_k_homo;
diff --git a/source/source_io/get_wf_lcao.cpp b/source/source_io/get_wf_lcao.cpp
index 6cafa72d60..91d2c0b514 100644
--- a/source/source_io/get_wf_lcao.cpp
+++ b/source/source_io/get_wf_lcao.cpp
@@ -513,7 +513,7 @@ void Get_wf_lcao::wfc_2d_to_grid(const T* lowf_2d,
     MPI_Comm_rank(pv.comm(), &rank);
 
     // calculate the maximum number of nlocal over all processes in pv.comm() range
-    long buf_size;
+    long buf_size = 0;
     mpi_info = MPI_Reduce(&pv.nloc_wfc, &buf_size, 1, MPI_LONG, MPI_MAX, 0, pv.comm());
     mpi_info = MPI_Bcast(&buf_size, 1, MPI_LONG, 0, pv.comm()); // get and then broadcast
     std::vector<T> lowf_block(buf_size);
diff --git a/source/source_io/read_input.cpp b/source/source_io/read_input.cpp
index a23bcd0da9..c08c63acc7 100644
--- a/source/source_io/read_input.cpp
+++ b/source/source_io/read_input.cpp
@@ -104,13 +104,13 @@ bool filter_nonascii_and_comment(std::ifstream& ifs,
     ifs.clear();
     ifs.seekg(0, std::ios::beg);
 
-	char c;
+	char c = '\0';
 	while (ifs.get(c)) 
 	{
 		// If comment start, skip until end of line (but keep the newline)
 		if (c == '#') 
 		{
-			char d;
+			char d = '\0';
 			bool newline_found = false;
 			while (ifs.get(d)) 
 			{
@@ -562,7 +562,7 @@ int ReadInput::current_md_step(const std::string& file_dir)
         ModuleBase::WARNING_QUIT("current_md_step", "no Restart_md.txt");
     }
 
-    int md_step;
+    int md_step = 0;
     file >> md_step;
     file.close();
 
diff --git a/source/source_io/to_qo_kernel.cpp b/source/source_io/to_qo_kernel.cpp
index b16917259a..8ce94520a1 100644
--- a/source/source_io/to_qo_kernel.cpp
+++ b/source/source_io/to_qo_kernel.cpp
@@ -598,7 +598,7 @@ void toQO::read_ovlp(const std::string& dir, const int& nrows, const int& ncols,
     {
         if (is_R)
         {
-            double val;
+            double val = 0.0;
             ifs >> val;
             inum++;
             if (inum <= nchi_ * nphi_) {
diff --git a/source/source_io/to_qo_mpi.cpp b/source/source_io/to_qo_mpi.cpp
index e8823a3ee5..c4a01cc693 100644
--- a/source/source_io/to_qo_mpi.cpp
+++ b/source/source_io/to_qo_mpi.cpp
@@ -7,7 +7,7 @@ void toQO::bcast_stdvector_ofvector3int(std::vector<ModuleBase::Vector3<int>>& v
                                         const int rank)
 {
     #ifdef __MPI
-    int dim;
+    int dim = 0;
     std::vector<int> vec_1d;
     if(rank == 0)
     {
@@ -37,7 +37,7 @@ void toQO::bcast_stdvector_ofvector3double(std::vector<ModuleBase::Vector3<doubl
                                            const int rank)
 {
     #ifdef __MPI
-    int dim;
+    int dim = 0;
     std::vector<double> vec_1d;
     if(rank == 0)
     {
diff --git a/source/source_io/to_qo_structures.cpp b/source/source_io/to_qo_structures.cpp
index 28679baf58..91f4cf4092 100644
--- a/source/source_io/to_qo_structures.cpp
+++ b/source/source_io/to_qo_structures.cpp
@@ -60,7 +60,7 @@ void toQO::read_structures(const UnitCell* p_ucell,
     }
     for(int i = 0; i < nranks; i++)
     {
-        int nks_dim;
+        int nks_dim = 0;
         if(iproc_ == 0) nks_dim = nks_divided[i].size();
         Parallel_Common::bcast_int(nks_dim);
         if(iproc_ != 0) nks_divided[i].resize(nks_dim);
@@ -244,7 +244,7 @@ void toQO::scan_supercell(const int& rank, const int& nranks)
     }
     for(int i = 0; i < nranks; i++)
     {
-        int nR_dim;
+        int nR_dim = 0;
         if(rank == 0) nR_dim = nR_divided[i].size();
         Parallel_Common::bcast_int(nR_dim);
         if(rank != 0) nR_divided[i].resize(nR_dim);
diff --git a/source/source_io/to_wannier90.cpp b/source/source_io/to_wannier90.cpp
index a3b814ed82..e7a291dcfc 100644
--- a/source/source_io/to_wannier90.cpp
+++ b/source/source_io/to_wannier90.cpp
@@ -202,7 +202,7 @@ bool toWannier90::try_read_nnkp(const UnitCell& ucell, const K_Vectors& kv)
             cal_num_kpts = num_kpts / 2;
         }
 
-        int numkpt_nnkp;
+        int numkpt_nnkp = 0;
         ModuleBase::GlobalFunc::READ_VALUE(nnkp_read, numkpt_nnkp);
         if ((PARAM.inp.nspin == 1 || PARAM.inp.nspin == 4) && numkpt_nnkp != num_kpts)
         {
@@ -433,7 +433,7 @@ bool toWannier90::try_read_nnkp(const UnitCell& ucell, const K_Vectors& kv)
             {
                 for (int ib = 0; ib < nntot; ib++)
                 {
-                    int ik_nnkp;
+                    int ik_nnkp = 0;
                     nnkp_read >> ik_nnkp;
                     if (ik_nnkp != (ik + 1))
                     {
diff --git a/source/source_io/unk_overlap_lcao.cpp b/source/source_io/unk_overlap_lcao.cpp
index eaab367041..99726117ff 100644
--- a/source/source_io/unk_overlap_lcao.cpp
+++ b/source/source_io/unk_overlap_lcao.cpp
@@ -96,7 +96,7 @@ void unkOverlap_lcao::init(const UnitCell& ucell,
     {
         local_term++;
     }
-    int start;
+    int start = 0;
     for (int rank = 0; rank < nproc; rank++)
     {
         if (rank == myrank)
diff --git a/source/source_lcao/module_deepks/deepks_orbital.cpp b/source/source_lcao/module_deepks/deepks_orbital.cpp
index 1a0d91cafe..7f16b6fec1 100644
--- a/source/source_lcao/module_deepks/deepks_orbital.cpp
+++ b/source/source_lcao/module_deepks/deepks_orbital.cpp
@@ -29,7 +29,7 @@ void DeePKS_domain::cal_o_delta(const std::vector<TH>& dm_hl,
 
                 if (mu >= 0 && nu >= 0)
                 {
-                    int iic;
+                    int iic = 0;
                     if (PARAM.inp.ks_solver == "genelpa" || PARAM.inp.ks_solver == "scalapack_gvx"
                         || PARAM.inp.ks_solver == "pexsi") // save the matrix as column major format
                     {
diff --git a/source/source_lcao/module_deepks/deepks_pdm.cpp b/source/source_lcao/module_deepks/deepks_pdm.cpp
index edbfec8ef8..fdc838f45a 100644
--- a/source/source_lcao/module_deepks/deepks_pdm.cpp
+++ b/source/source_lcao/module_deepks/deepks_pdm.cpp
@@ -53,7 +53,7 @@ void DeePKS_domain::read_pdm(bool read_pdm_file,
                 {
                     for (int m2 = 0; m2 < nm; m2++)
                     {
-                        double c;
+                        double c = 0.0;
                         ifs >> c;
                         accessor[m1][m2] = c;
                     }
@@ -74,7 +74,7 @@ void DeePKS_domain::read_pdm(bool read_pdm_file,
                 auto accessor = pdm[iat].accessor<double, 1>();
                 for (int ind = 0; ind < pdm_size; ind++)
                 {
-                    double c;
+                    double c = 0.0;
                     ifs >> c;
                     accessor[ind] = c;
                 }
diff --git a/source/source_lcao/module_deepks/deepks_vdelta.cpp b/source/source_lcao/module_deepks/deepks_vdelta.cpp
index ba9f35f9fc..ab0f94c3a4 100644
--- a/source/source_lcao/module_deepks/deepks_vdelta.cpp
+++ b/source/source_lcao/module_deepks/deepks_vdelta.cpp
@@ -38,7 +38,7 @@ void DeePKS_domain::cal_e_delta_band(const std::vector<std::vector<TK>>& dm,
 
             if (mu >= 0 && nu >= 0)
             {
-                int iic;
+                int iic = 0;
                 if (ModuleBase::GlobalFunc::IS_COLUMN_MAJOR_KS_SOLVER(PARAM.inp.ks_solver))
                 {
                     iic = mu + nu * pv->nrow;
diff --git a/source/source_lcao/module_deltaspin/lambda_loop.cpp b/source/source_lcao/module_deltaspin/lambda_loop.cpp
index 8b87f7eedd..5d38c5d261 100644
--- a/source/source_lcao/module_deltaspin/lambda_loop.cpp
+++ b/source/source_lcao/module_deltaspin/lambda_loop.cpp
@@ -117,9 +117,7 @@ void spinconstrain::SpinConstrain<std::complex<double>>::run_lambda_loop(
     std::vector<ModuleBase::Vector3<double>> new_spin(nat, 0.0), spin_plus(nat, 0.0);
 
     double alpha_opt, alpha_plus;
-    double beta;
-    double mean_error, mean_error_old, rms_error;
-    double g;
+    double beta = 0.0, g = 0.0, mean_error = 0.0, mean_error_old = 0.0, rms_error = 0.0;
 
     double alpha_trial = this->alpha_trial_;
 
diff --git a/source/source_lcao/module_dftu/dftu_folding.cpp b/source/source_lcao/module_dftu/dftu_folding.cpp
index b67db9fcb4..cba6b33991 100644
--- a/source/source_lcao/module_dftu/dftu_folding.cpp
+++ b/source/source_lcao/module_dftu/dftu_folding.cpp
@@ -246,7 +246,7 @@ void Plus_U::folding_matrix_k(const UnitCell& ucell,
 								continue;
 							}
 
-                            int iic;
+                            int iic = 0;
                             if (ModuleBase::GlobalFunc::IS_COLUMN_MAJOR_KS_SOLVER(PARAM.inp.ks_solver))
                             {
                                 iic = mu + nu * pv.nrow;
diff --git a/source/source_lcao/module_dftu/dftu_io.cpp b/source/source_lcao/module_dftu/dftu_io.cpp
index f75bc408c6..737c1c590a 100644
--- a/source/source_lcao/module_dftu/dftu_io.cpp
+++ b/source/source_lcao/module_dftu/dftu_io.cpp
@@ -487,7 +487,7 @@ inline void JacobiRotate(std::vector<std::vector<double>>& A, int p, int q, int
 	if (std::abs(A[p][q]) > 1e-10) 
 	{
 		double r = (A[q][q] - A[p][p]) / (2.0 * A[p][q]);
-        double t;
+        double t = 0.0;
         if (r >= 0) {
             t = 1.0 / (r + sqrt(1.0 + r * r));
         } else {
diff --git a/source/source_lcao/module_gint/gint_common.cpp b/source/source_lcao/module_gint/gint_common.cpp
index 69957f0b38..3588604f59 100644
--- a/source/source_lcao/module_gint/gint_common.cpp
+++ b/source/source_lcao/module_gint/gint_common.cpp
@@ -316,7 +316,7 @@ void wfc_2d_to_gint(const T* wfc_2d,
     MPI_Comm_rank(pv.comm(), &rank);
 
     // calculate the maximum number of nlocal over all processes in pv.comm() range
-    long buf_size;
+    long buf_size = 0;
     mpi_info = MPI_Reduce(&pv.nloc_wfc, &buf_size, 1, MPI_LONG, MPI_MAX, 0, pv.comm());
     mpi_info = MPI_Bcast(&buf_size, 1, MPI_LONG, 0, pv.comm()); // get and then broadcast
     std::vector<T> wfc_block(buf_size);
diff --git a/source/source_lcao/module_gint/gint_dvlocal.cpp b/source/source_lcao/module_gint/gint_dvlocal.cpp
index 3d3888a0b9..7910649b71 100644
--- a/source/source_lcao/module_gint/gint_dvlocal.cpp
+++ b/source/source_lcao/module_gint/gint_dvlocal.cpp
@@ -72,7 +72,7 @@ void Gint_dvlocal::cal_dvlocal_R_sparseMatrix(
     std::map<Abfs::Vector3_Order<int>, std::map<size_t, std::map<size_t, double>>> pvdpRy_sparseMatrix;
     std::map<Abfs::Vector3_Order<int>, std::map<size_t, std::map<size_t, double>>> pvdpRz_sparseMatrix;
     
-    double temp_value_double;
+    double temp_value_double = 0.0;
 
     Vec3d tau1, dtau;
     for (int iap = 0; iap < pvdpRx.size_atom_pairs(); iap++)
diff --git a/source/source_lcao/module_gint/set_ddphi.cpp b/source/source_lcao/module_gint/set_ddphi.cpp
index c84f087487..4e7d486fbc 100644
--- a/source/source_lcao/module_gint/set_ddphi.cpp
+++ b/source/source_lcao/module_gint/set_ddphi.cpp
@@ -72,7 +72,7 @@ void GintAtom::set_ddphi(
             const double x12 = x1 * x2 / 6;
             const double x03 = x0 * x3 / 2;
 
-            double tmp, dtmp;
+            double tmp = 0.0, dtmp = 0.0;
 
             for(int iw = 0; iw < atom_->nw; ++iw)
             {
diff --git a/source/source_lcao/module_hcontainer/func_folding.cpp b/source/source_lcao/module_hcontainer/func_folding.cpp
index 58ba3d267a..4b276846d6 100644
--- a/source/source_lcao/module_hcontainer/func_folding.cpp
+++ b/source/source_lcao/module_hcontainer/func_folding.cpp
@@ -40,7 +40,7 @@ void folding_HR(const hamilt::HContainer<TR>& hR,
             // if TK==std::complex<double>, kphase is e^{ikR}
             const ModuleBase::Vector3<double> dR(r_index.x, r_index.y, r_index.z);
             const double arg = (kvec_d_in * dR) * ModuleBase::TWO_PI;
-            double sinp, cosp;
+            double sinp = 0.0, cosp = 0.0;
             ModuleBase::libm::sincos(arg, &sinp, &cosp);
             std::complex<double> kphase = std::complex<double>(cosp, sinp);
             
@@ -86,7 +86,7 @@ void folding_HR(const hamilt::HContainer<TR>& hR,
         // if TK==std::complex<double>, kphase is e^{ikR}
         const ModuleBase::Vector3<double> dR(rx, ry, rz);
         const double arg = (kvec_d_in * dR) * ModuleBase::TWO_PI;
-        double sinp, cosp;
+        double sinp = 0.0, cosp = 0.0;
         ModuleBase::libm::sincos(arg, &sinp, &cosp);
         std::complex<double> kphase = std::complex<double>(cosp, sinp);
 
diff --git a/source/source_lcao/module_hcontainer/func_transfer.cpp b/source/source_lcao/module_hcontainer/func_transfer.cpp
index 1da0c524a1..14566ac01d 100644
--- a/source/source_lcao/module_hcontainer/func_transfer.cpp
+++ b/source/source_lcao/module_hcontainer/func_transfer.cpp
@@ -169,7 +169,7 @@ void transferParallels2Serial(const hamilt::HContainer<TR>& hR_p, hamilt::HConta
 
     // send data
     std::vector<TR> receive_values;
-    long max_size;
+    long max_size = 0;
     if (my_rank == serial_rank)
     {
         max_size = trans_s->get_max_size();
diff --git a/source/source_lcao/module_hcontainer/test/test_hcontainer.cpp b/source/source_lcao/module_hcontainer/test/test_hcontainer.cpp
index 536eb8744e..ef948f87d8 100644
--- a/source/source_lcao/module_hcontainer/test/test_hcontainer.cpp
+++ b/source/source_lcao/module_hcontainer/test/test_hcontainer.cpp
@@ -542,8 +542,8 @@ TEST_F(HContainerTest, atompair_funcs)
     }
     HR.unfix_R();
     // check hr_array and hr_array2 are correct
-    std::complex<double> correct1;
-    double correct2;
+    std::complex<double> correct1 = 0.0;
+    double correct2 = 0.0;
     double correct_array[16] = {
         1, 2, 3, 4, 
         5, 6, 7, 8, 
diff --git a/source/source_lcao/module_lr/dm_trans/dmr_complex.cpp b/source/source_lcao/module_lr/dm_trans/dmr_complex.cpp
index 3ed8ab69bf..4f62aa2a43 100644
--- a/source/source_lcao/module_lr/dm_trans/dmr_complex.cpp
+++ b/source/source_lcao/module_lr/dm_trans/dmr_complex.cpp
@@ -47,7 +47,7 @@ namespace elecstate
                             // if TK==std::complex<double>, kphase is e^{ikR}
                             const ModuleBase::Vector3<double> dR(r_index[0], r_index[1], r_index[2]);
                             const double arg = (this->_kvec_d[ik] * dR) * ModuleBase::TWO_PI;
-                            double sinp, cosp;
+                            double sinp = 0.0, cosp = 0.0;
                             ModuleBase::libm::sincos(arg, &sinp, &cosp);
                             const std::complex<double> kphase = std::complex<double>(cosp, sinp);
                             // set DMR element
diff --git a/source/source_lcao/module_lr/esolver_lrtd_lcao.cpp b/source/source_lcao/module_lr/esolver_lrtd_lcao.cpp
index 16efc5f046..95b956b7fb 100644
--- a/source/source_lcao/module_lr/esolver_lrtd_lcao.cpp
+++ b/source/source_lcao/module_lr/esolver_lrtd_lcao.cpp
@@ -692,7 +692,7 @@ void LR::ESolver_LR<T, TR>::read_ks_chg(Charge& chg_gs)
         std::stringstream ssc;
         ssc << PARAM.globalv.global_readin_dir << "SPIN" << is + 1 << "_CHG.cube";
         GlobalV::ofs_running << ssc.str() << std::endl;
-        double ef;
+        double ef = 0.0;
         if (ModuleIO::read_vdata_palgrid(Pgrid,
             GlobalV::MY_RANK,
             GlobalV::ofs_running,
diff --git a/source/source_lcao/module_lr/utils/lr_util.cpp b/source/source_lcao/module_lr/utils/lr_util.cpp
index ae2f00ffa3..f720012413 100644
--- a/source/source_lcao/module_lr/utils/lr_util.cpp
+++ b/source/source_lcao/module_lr/utils/lr_util.cpp
@@ -120,7 +120,7 @@ namespace LR_Util
         ModuleBase::TITLE("LR_Util", "diag_lapack<double>");
         int info = 0;
         char jobz = 'V', uplo = 'U';
-        double work_tmp;
+        double work_tmp = 0.0;
         const int minus_one = -1;
         dsyev_(&jobz, &uplo, &n, mat, &n, eig, &work_tmp, &minus_one, &info);		// get best lwork
         const int lwork = work_tmp;
@@ -149,7 +149,7 @@ namespace LR_Util
         ModuleBase::TITLE("LR_Util", "diag_lapack_nh<double>");
         int info = 0;
         char jobvl = 'N', jobvr = 'V';  //calculate right eigenvectors
-        double work_tmp;
+        double work_tmp = 0.0;
         const int minus_one = -1;
         std::vector<double> eig_real(n);
         std::vector<double> eig_imag(n);
diff --git a/source/source_lcao/module_operator_lcao/dftu_force_stress.hpp b/source/source_lcao/module_operator_lcao/dftu_force_stress.hpp
index 2ce46854a4..8175d1009f 100644
--- a/source/source_lcao/module_operator_lcao/dftu_force_stress.hpp
+++ b/source/source_lcao/module_operator_lcao/dftu_force_stress.hpp
@@ -324,7 +324,7 @@ void DFTU<OperatorLCAO<TK, TR>>::cal_force_IJR(const int& iat1,
         step_trace[3] = col_indexes.size() + 1;
     }
 
-    double tmp[3];
+    double tmp[3] = {0.0};
     // calculate the local matrix
     for (int is = 0; is < nspin; is++)
     {
diff --git a/source/source_lcao/module_operator_lcao/dspin_force_stress.hpp b/source/source_lcao/module_operator_lcao/dspin_force_stress.hpp
index ff14029e25..449d73c050 100644
--- a/source/source_lcao/module_operator_lcao/dspin_force_stress.hpp
+++ b/source/source_lcao/module_operator_lcao/dspin_force_stress.hpp
@@ -272,7 +272,7 @@ void DeltaSpin<OperatorLCAO<TK, TR>>::cal_force_IJR(const int& iat1,
         step_trace[2] = col_indexes.size();
         step_trace[3] = col_indexes.size() + 1;
     }
-    double tmp[3];
+    double tmp[3] = {0.0};
     // calculate the local matrix
     for (int is = 1; is < nspin; is++)
     {
diff --git a/source/source_lcao/module_ri/exx_abfs-io.cpp b/source/source_lcao/module_ri/exx_abfs-io.cpp
index 0ed196335b..bbdda73897 100644
--- a/source/source_lcao/module_ri/exx_abfs-io.cpp
+++ b/source/source_lcao/module_ri/exx_abfs-io.cpp
@@ -62,7 +62,7 @@ std::vector<std::vector<Numerical_Orbital_Lm>> Exx_Abfs::IO::construct_abfs_T(
 	size_t L_size;
 	std::map<size_t,size_t> N_size;
 	size_t meshr;
-	double dr;
+	double dr = 0.0;
 	std::map<size_t,std::map<size_t,std::vector<double>>> psis;
 	
 	/*----------------------
diff --git a/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector.cpp b/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector.cpp
index b79bfcfc20..f93b8aa040 100644
--- a/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector.cpp
+++ b/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector.cpp
@@ -235,4 +235,4 @@ namespace ModuleSymmetry
         // this->output_sector_star();
         this->write_irreducible_sector();
     }
-}
\ No newline at end of file
+}
diff --git a/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector_bvk.cpp b/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector_bvk.cpp
index 50df31b360..8b8879ee1d 100644
--- a/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector_bvk.cpp
+++ b/source/source_lcao/module_ri/module_exx_symmetry/irreducible_sector_bvk.cpp
@@ -102,8 +102,8 @@ namespace ModuleSymmetry
 }
 
         // analyze bravis and generate optimized lattice for minimal BvK lattice
-        double cel_const[6];
-        double pre_const[6];
+        double cel_const[6] = {0.0};
+        double pre_const[6] = {0.0};
         int bvk_brav = 0;
         std::string bvk_latname="";
         // bvk_brav = symm.standard_lat(s1, s2, s3, cel_const); //not enough, optimal lattice may change after cell-extension
@@ -126,10 +126,10 @@ namespace ModuleSymmetry
 
         // generate symmetry operation of the BvK lattice using the original optlat-direct coordinates
         std::vector<ModuleBase::Matrix3> bvk_op(48);
-        int bvk_nop;
+        int bvk_nop = 0;
         symm.setgroup(bvk_op.data(), bvk_nop, bvk_brav);
         bvk_op.resize(bvk_nop);
-        int bvk_npg, bvk_nsg, bvk_pgnum, bvk_sgnum;
+        int bvk_npg = 0, bvk_nsg = 0, bvk_pgnum = 0, bvk_sgnum = 0;
         std::string bvk_pgname, bvk_sgname;
         std::vector<ModuleBase::Matrix3> bvk_gmatrix(48);
         std::vector<ModuleBase::Vector3<double>> bvk_gtrans(48);
diff --git a/source/source_lcao/module_ri/module_exx_symmetry/symmetry_rotation.cpp b/source/source_lcao/module_ri/module_exx_symmetry/symmetry_rotation.cpp
index e0b4d91b8b..27929737f6 100644
--- a/source/source_lcao/module_ri/module_exx_symmetry/symmetry_rotation.cpp
+++ b/source/source_lcao/module_ri/module_exx_symmetry/symmetry_rotation.cpp
@@ -203,7 +203,7 @@ namespace ModuleSymmetry
     TCdouble Symmetry_rotation::get_euler_angle(const ModuleBase::Matrix3& gmatc) const
     {
         double threshold = this->eps_;
-        double alpha, beta, gamma;
+        double alpha = 0.0, beta = 0.0, gamma = 0.0;
         if (std::fabs(gmatc.e32) > threshold || std::fabs(gmatc.e31) > threshold) // sin(beta) is not zero
         {
             // use the 2-angle elements to get alpha and gamma
diff --git a/source/source_lcao/module_rt/boundary_fix.cpp b/source/source_lcao/module_rt/boundary_fix.cpp
index 22e7324633..dcdb436153 100644
--- a/source/source_lcao/module_rt/boundary_fix.cpp
+++ b/source/source_lcao/module_rt/boundary_fix.cpp
@@ -33,7 +33,7 @@ void reset_matrix_boundary(const UnitCell& ucell,
                 //skip unrelevent ik
                 if(arg==0)continue;
                 //calculate correction phase
-                double sinp, cosp;
+                double sinp = 0.0, cosp = 0.0;
                 ModuleBase::libm::sincos(arg, &sinp, &cosp);
                 const std::complex<double> phase = std::complex<double>(cosp, sinp);
                 //phase correction for Hamiltionian, overlap matrix and c vec.
diff --git a/source/source_lcao/module_rt/norm_psi.cpp b/source/source_lcao/module_rt/norm_psi.cpp
index 307cef9f80..d29972dce3 100644
--- a/source/source_lcao/module_rt/norm_psi.cpp
+++ b/source/source_lcao/module_rt/norm_psi.cpp
@@ -16,7 +16,7 @@ namespace module_rt
 
 inline int globalIndex(int localindex, int nblk, int nprocs, int myproc)
 {
-    int iblock, gIndex;
+    int iblock = 0, gIndex = 0;
     iblock = localindex / nblk;
     gIndex = (iblock * nprocs + myproc) * nblk + localindex % nblk;
     return gIndex;
diff --git a/source/source_lcao/module_rt/propagator.cpp b/source/source_lcao/module_rt/propagator.cpp
index d9a37b8c8b..2854839066 100644
--- a/source/source_lcao/module_rt/propagator.cpp
+++ b/source/source_lcao/module_rt/propagator.cpp
@@ -24,7 +24,7 @@ void Propagator::compute_propagator(const int nlocal,
                                     std::ofstream& ofs_running,
                                     const int print_matrix) const
 {
-    int tag;
+    int tag = 0;
     switch (ptype)
     {
     case 0:
@@ -56,7 +56,7 @@ void Propagator::compute_propagator_tensor(const int nlocal,
                                            const int print_matrix,
                                            const bool use_lapack) const
 {
-    int tag;
+    int tag = 0;
     switch (ptype)
     {
     case 0:
diff --git a/source/source_lcao/module_rt/td_folding.cpp b/source/source_lcao/module_rt/td_folding.cpp
index e0b34cd31f..ed42b7524e 100644
--- a/source/source_lcao/module_rt/td_folding.cpp
+++ b/source/source_lcao/module_rt/td_folding.cpp
@@ -32,7 +32,7 @@ void folding_HR_td(const UnitCell& ucell,
             // if TK==std::complex<double>, kphase is e^{ikR}
             const ModuleBase::Vector3<double> dR(r_index.x, r_index.y, r_index.z);
             const double arg = (kvec_d_in * dR) * ModuleBase::TWO_PI + arg_td;
-            double sinp, cosp;
+            double sinp = 0.0, cosp = 0.0;
             ModuleBase::libm::sincos(arg, &sinp, &cosp);
             std::complex<double> kphase = std::complex<double>(cosp, sinp);
 
@@ -62,7 +62,7 @@ void folding_partial_HR(const UnitCell& ucell,
             const ModuleBase::Vector3<int> r_index = tmp.get_R_index(ir);
             const ModuleBase::Vector3<double> dR(r_index.x, r_index.y, r_index.z);
             const double arg = (kvec_d_in * dR) * ModuleBase::TWO_PI;
-            double sinp, cosp;
+            double sinp = 0.0, cosp = 0.0;
             ModuleBase::libm::sincos(arg, &sinp, &cosp);
             std::complex<double> kphase = std::complex<double>(cosp, sinp);
             const ModuleBase::Vector3<double> dR_car = dR * ucell.latvec * ucell.lat0;
@@ -105,7 +105,7 @@ void folding_partial_HR_td(const UnitCell& ucell,
             // if TK==std::complex<double>, kphase is e^{ikR}
             const ModuleBase::Vector3<double> dR(r_index.x, r_index.y, r_index.z);
             const double arg = (kvec_d_in * dR) * ModuleBase::TWO_PI + arg_td;
-            double sinp, cosp;
+            double sinp = 0.0, cosp = 0.0;
             ModuleBase::libm::sincos(arg, &sinp, &cosp);
             std::complex<double> kphase = std::complex<double>(cosp, sinp);
             const ModuleBase::Vector3<double> dR_car = dR * ucell.latvec * ucell.lat0;
diff --git a/source/source_lcao/module_rt/velocity_op.cpp b/source/source_lcao/module_rt/velocity_op.cpp
index ceec0b1b65..7114fb2495 100644
--- a/source/source_lcao/module_rt/velocity_op.cpp
+++ b/source/source_lcao/module_rt/velocity_op.cpp
@@ -54,7 +54,7 @@ void Velocity_op<TR>::initialize_vcomm_r(const Grid_Driver* GridD, const Paralle
     for (int iat0 = 0; iat0 < ucell->nat; iat0++)
     {
         auto tau0 = ucell->get_tau(iat0);
-        int T0, I0;
+        int T0 = 0, I0 = 0;
         ucell->iat2iait(iat0, &I0, &T0);
         AdjacentAtomInfo adjs;
         GridD->Find_atom(*ucell, tau0, T0, I0, &adjs);
@@ -129,7 +129,7 @@ void Velocity_op<TR>::initialize_grad_term(const Grid_Driver* GridD, const Paral
     for (int iat1 = 0; iat1 < ucell->nat; iat1++)
     {
         auto tau1 = ucell->get_tau(iat1);
-        int T1, I1;
+        int T1 = 0, I1 = 0;
         ucell->iat2iait(iat1, &I1, &T1);
         AdjacentAtomInfo adjs;
         GridD->Find_atom(*ucell, tau1, T1, I1, &adjs);
@@ -190,7 +190,7 @@ void Velocity_op<TR>::calculate_vcomm_r()
     for (int iat0 = 0; iat0 < this->ucell->nat; iat0++)
     {
         auto tau0 = ucell->get_tau(iat0);
-        int T0, I0;
+        int T0 = 0, I0 = 0;
         ucell->iat2iait(iat0, &I0, &T0);
         AdjacentAtomInfo& adjs = this->adjs_vcommr[iat0];
         std::vector<std::vector<std::unordered_map<int, std::vector<double>>>> nlm_tot;
@@ -422,7 +422,7 @@ void Velocity_op<TR>::calculate_grad_term()
     for (int iat1 = 0; iat1 < this->ucell->nat; iat1++)
     {
         auto tau1 = ucell->get_tau(iat1);
-        int T1, I1;
+        int T1 = 0, I1 = 0;
         ucell->iat2iait(iat1, &I1, &T1);
         AdjacentAtomInfo& adjs = this->adjs_grad[iat1];
         for (int ad = 0; ad < adjs.adj_num + 1; ++ad)
@@ -464,9 +464,9 @@ void Velocity_op<TR>::cal_grad_IJR(const int& iat1,
     // ---------------------------------------------
     // get info of orbitals of atom1 and atom2 from ucell
     // ---------------------------------------------
-    int T1, I1;
+    int T1 = 0, I1 = 0;
     this->ucell->iat2iait(iat1, &I1, &T1);
-    int T2, I2;
+    int T2 = 0, I2 = 0;
     this->ucell->iat2iait(iat2, &I2, &T2);
     Atom& atom1 = this->ucell->atoms[T1];
     Atom& atom2 = this->ucell->atoms[T2];
diff --git a/source/source_lcao/spar_dh.cpp b/source/source_lcao/spar_dh.cpp
index 7d5d485d56..1848901eea 100644
--- a/source/source_lcao/spar_dh.cpp
+++ b/source/source_lcao/spar_dh.cpp
@@ -160,8 +160,8 @@ void sparse_format::cal_dSTN_R(const UnitCell& ucell,
     ModuleBase::Vector3<double> dtau, tau1, tau2;
     ModuleBase::Vector3<double> dtau1, dtau2, tau0;
 
-    double temp_value_double;
-    std::complex<double> temp_value_complex;
+    double temp_value_double = 0.0;
+    std::complex<double> temp_value_complex = 0.0;
 
     for (int T1 = 0; T1 < ucell.ntype; ++T1)
     {
diff --git a/source/source_lcao/spar_hsr.cpp b/source/source_lcao/spar_hsr.cpp
index fb74a15f23..c7e26791d4 100644
--- a/source/source_lcao/spar_hsr.cpp
+++ b/source/source_lcao/spar_hsr.cpp
@@ -11,7 +11,7 @@
 #ifdef __MPI
 void sparse_format::sync_all_R_coor(std::set<Abfs::Vector3_Order<int>>& all_R_coor, MPI_Comm comm)
 {
-    int my_rank, nproc;
+    int my_rank = 0, nproc = 0;
     MPI_Comm_rank(comm, &my_rank);
     MPI_Comm_size(comm, &nproc);
 
diff --git a/source/source_lcao/wavefunc_in_pw.cpp b/source/source_lcao/wavefunc_in_pw.cpp
index 701f0f42a4..3bc3711e14 100644
--- a/source/source_lcao/wavefunc_in_pw.cpp
+++ b/source/source_lcao/wavefunc_in_pw.cpp
@@ -125,7 +125,7 @@ void Wavefunc_in_pw::make_table_q(
 					}
 					else
 					{
-						 double no_use;
+						 double no_use = 0.0;
 						 for(int ir=0; ir<meshr_read; ir++)
 						 {
 							 in >> no_use;
@@ -327,7 +327,7 @@ void Wavefunc_in_pw::produce_local_basis_in_pw(const UnitCell& ucell,
 								}//if
 								else
 								{//atomic_wfc_so_mag
-									double alpha, gamma;
+									double alpha = 0.0, gamma = 0.0;
 									std::complex<double> fup,fdown;
                               		//int nc;
                               		//This routine creates two functions only in the case j=l+1/2 or exit in the other case
@@ -402,8 +402,8 @@ void Wavefunc_in_pw::produce_local_basis_in_pw(const UnitCell& ucell,
 							} // end if ucell.atoms[it].has_so
 							else
 							{//atomic_wfc_nc
-								double alpha, gamman;
-								std::complex<double> fup, fdown;
+								double alpha = 0.0, gamman = 0.0;
+								std::complex<double> fup = 0.0, fdown = 0.0;
 								//alpha = ucell.magnet.angle1_[it];
 								//gamman = -ucell.magnet.angle2_[it] + 0.5*ModuleBase::PI;
 								alpha = ucell.atoms[it].angle1[ia];
diff --git a/source/source_md/msst.cpp b/source/source_md/msst.cpp
index 0a9024cdfe..cadea1a8f1 100644
--- a/source/source_md/msst.cpp
+++ b/source/source_md/msst.cpp
@@ -83,7 +83,7 @@ void MSST::first_half(std::ofstream& ofs)
 
     const int sd = mdp.msst_direction;
     const double dthalf = 0.5 * md_dt;
-    double vol;
+    double vol = 0.0;
     energy_ = potential + kinetic;
 
     /// propagate the time derivative of volume 1/2 step
diff --git a/source/source_md/nhchain.cpp b/source/source_md/nhchain.cpp
index dfe086490a..ac1e23570c 100644
--- a/source/source_md/nhchain.cpp
+++ b/source/source_md/nhchain.cpp
@@ -390,7 +390,7 @@ void Nose_Hoover::restart(const std::string& global_readin_dir)
 
         if (ok)
         {
-            double Mnum;
+            double Mnum = 0.0;
             file >> step_rst_ >> md_tfirst >> Mnum;
 
             if (Mnum != mdp.md_tchain)
@@ -494,7 +494,7 @@ void Nose_Hoover::particle_thermo()
     }
 
     /// integrate loop
-    double factor;
+    double factor = 0.0;
     double scale = 1.0;
     double KE = kinetic;
     for (int i = 0; i < nc_tchain; ++i)
@@ -583,7 +583,7 @@ void Nose_Hoover::baro_thermo()
     g_peta[0] = (ke_omega - lkt_press) / mass_peta[0];
 
     /// integrate loop
-    double factor;
+    double factor = 0.0;
     double scale = 1.0;
     double kecurrent = ke_omega;
     for (int i = 0; i < nc_pchain; ++i)
@@ -662,7 +662,7 @@ void Nose_Hoover::update_baro()
     }
     term_one /= pdim * ucell.nat;
 
-    double g_omega;
+    double g_omega = 0.0;
     double term_two = 0;
     for (int i = 0; i < 3; ++i)
     {
@@ -689,7 +689,7 @@ void Nose_Hoover::update_baro()
 
 void Nose_Hoover::vel_baro()
 {
-    double factor[3];
+    double factor[3] = {0.0};
     for (int i = 0; i < 3; ++i)
     {
         factor[i] = exp(-(v_omega[i] + mtk_term) * md_dt / 4);
@@ -721,7 +721,7 @@ void Nose_Hoover::vel_baro()
 
 void Nose_Hoover::update_volume(std::ofstream& ofs)
 {
-    double factor;
+    double factor = 0.0;
 
     /// tri mode, off-diagonal components, first half
     if (pflag[4])
diff --git a/source/source_md/verlet.cpp b/source/source_md/verlet.cpp
index 3eafb181e1..66871f8970 100644
--- a/source/source_md/verlet.cpp
+++ b/source/source_md/verlet.cpp
@@ -75,7 +75,7 @@ void Verlet::apply_thermostat(void)
     {
         if (my_rank == 0)
         {
-            double deviation;
+            double deviation = 0.0;
             for (int i = 0; i < ucell.nat; ++i)
             {
                 if (static_cast<double>(std::rand()) / RAND_MAX <= 1.0 / mdp.md_nraise)
diff --git a/source/source_psi/psi_initializer_nao.cpp b/source/source_psi/psi_initializer_nao.cpp
index 7f74b40c44..bd0a29e7d1 100644
--- a/source/source_psi/psi_initializer_nao.cpp
+++ b/source/source_psi/psi_initializer_nao.cpp
@@ -85,9 +85,9 @@ void psi_initializer_nao<T>::read_external_orbs(const std::string* orbital_files
                                  << this->orbital_files_[it] << std::endl;
         }
         std::string elem; // garbage value, will discard
-        double ecut;      // garbage value, will discard
-        int nr;
-        double dr;
+        double ecut = 0.0;      // garbage value, will discard
+        int nr = 0;
+        double dr = 0.0;
         std::vector<int> nzeta;
         std::vector<std::vector<double>> radials;
         ModuleIO::read_abacus_orb(ifs_it, elem, ecut, nr, dr, nzeta, radials, rank);
diff --git a/source/source_pw/module_pwdft/elecond.cpp b/source/source_pw/module_pwdft/elecond.cpp
index 068ca01067..985f7f8717 100644
--- a/source/source_pw/module_pwdft/elecond.cpp
+++ b/source/source_pw/module_pwdft/elecond.cpp
@@ -61,7 +61,7 @@ void EleCond<FPTYPE, Device>::KG(const int& smear_type,
     const double gamma = fwhmin / 2.0 / ModuleBase::Ry_to_eV;
     double dt = dt_in;           // unit in a.u., 1 a.u. = 4.837771834548454e-17 s
     const double expfactor = 23; // exp(-23) = 1e-10
-    int nt;                      // set nt empirically
+    int nt = 0;                  // set nt empirically
     if (smear_type == 1)
     {
         nt = ceil(sqrt(2 * expfactor) / sigma / dt);
diff --git a/source/source_pw/module_pwdft/forces.cpp b/source/source_pw/module_pwdft/forces.cpp
index 255b8e23a2..fbcebe6304 100644
--- a/source/source_pw/module_pwdft/forces.cpp
+++ b/source/source_pw/module_pwdft/forces.cpp
@@ -197,7 +197,7 @@ void Forces<FPTYPE, Device>::cal_force(UnitCell& ucell,
 
     if (ModuleSymmetry::Symmetry::symm_flag == 1)
     {
-        double d1, d2, d3;
+        double d1 = 0.0, d2 = 0.0, d3 = 0.0;
         for (int iat = 0; iat < this->nat; iat++)
         {
             ModuleBase::Mathzone::Cartesian_to_Direct(force(iat, 0),
@@ -449,7 +449,7 @@ void Forces<FPTYPE, Device>::cal_force_loc(const UnitCell& ucell,
             for (int ig = 0; ig < rho_basis->npw; ig++)
             {
                 const double phase = ModuleBase::TWO_PI * (rho_basis->gcar[ig] * ucell.atoms[it].tau[ia]);
-                double sinp, cosp;
+                double sinp = 0.0, cosp = 0.0;
                 ModuleBase::libm::sincos(phase, &sinp, &cosp);
                 const double factor
                     = vloc(it, rho_basis->ig2igg[ig]) * (cosp * aux[ig].imag() + sinp * aux[ig].real());
@@ -503,7 +503,7 @@ void Forces<FPTYPE, Device>::cal_force_ew(const UnitCell& ucell,
         {
             if (ucell.atoms[it].na != 0)
             {
-                double dzv;
+                double dzv = 0.0;
                 {
                     dzv = ucell.atoms[it].ncpp.zv;
                 }
@@ -526,7 +526,7 @@ void Forces<FPTYPE, Device>::cal_force_ew(const UnitCell& ucell,
     }
 
     double alpha = 1.1;
-    double upperbound;
+    double upperbound = 0.0;
     do
     {
         alpha -= 0.10;
@@ -634,7 +634,7 @@ void Forces<FPTYPE, Device>::cal_force_ew(const UnitCell& ucell,
                 {
                     const ModuleBase::Vector3<double> gcar = rho_basis->gcar[ig];
                     const double arg = ModuleBase::TWO_PI * (gcar * ucell.atoms[it].tau[ia]);
-                    double sinp, cosp;
+                    double sinp = 0.0, cosp = 0.0;
                     ModuleBase::libm::sincos(arg, &sinp, &cosp);
                     double sumnb = -cosp * aux[ig].imag() + sinp * aux[ig].real();
                     forceion(iat, 0) += gcar[0] * sumnb;
@@ -686,7 +686,7 @@ void Forces<FPTYPE, Device>::cal_force_ew(const UnitCell& ucell,
                         {
                             const double rr = sqrt(r2[n]) * ucell.lat0;
 
-                            double factor;
+                            double factor = 0.0;
                             {
                                 factor = ucell.atoms[T1].ncpp.zv * ucell.atoms[T2].ncpp.zv
                                             * ModuleBase::e2 / (rr * rr)
diff --git a/source/source_pw/module_pwdft/forces_cc.cpp b/source/source_pw/module_pwdft/forces_cc.cpp
index a03d49964b..fd8b3ac20c 100644
--- a/source/source_pw/module_pwdft/forces_cc.cpp
+++ b/source/source_pw/module_pwdft/forces_cc.cpp
@@ -254,7 +254,7 @@ void Forces<FPTYPE, Device>::deriv_drhoc
     const UnitCell& ucell_in
 )
 {
-	int  igl0;
+	int  igl0 = 0;
 	double gx = 0, rhocg1 = 0;
 	//double *aux = new double[mesh];
 	std::vector<double> aux(mesh);
diff --git a/source/source_pw/module_pwdft/forces_scc.cpp b/source/source_pw/module_pwdft/forces_scc.cpp
index 10681e5114..d77ee3bf2a 100644
--- a/source/source_pw/module_pwdft/forces_scc.cpp
+++ b/source/source_pw/module_pwdft/forces_scc.cpp
@@ -114,7 +114,7 @@ void Forces<FPTYPE, Device>::cal_force_scc(ModuleBase::matrix& forcescc,
 						const double rhocgntigg
 							= rhocgnt[rho_basis->ig2igg[ig]];
 						const double arg = ModuleBase::TWO_PI * (gv * pos);
-						double sinp, cosp;
+						double sinp = 0.0, cosp = 0.0;
 						ModuleBase::libm::sincos(arg, &sinp, &cosp);
 						const std::complex<double> cpm
 							= std::complex<double>(sinp, cosp) * conj(psic[ig]);
diff --git a/source/source_pw/module_pwdft/fs_nonlocal_tools.h b/source/source_pw/module_pwdft/fs_nonlocal_tools.h
index 5a96f71fb9..a5307dbace 100644
--- a/source/source_pw/module_pwdft/fs_nonlocal_tools.h
+++ b/source/source_pw/module_pwdft/fs_nonlocal_tools.h
@@ -154,13 +154,13 @@ class FS_Nonlocal_tools
     Device* ctx = {};
     base_device::DEVICE_CPU* cpu_ctx = {};
     base_device::AbacusDevice_t device = {};
-    int nkb;
-    int nbands;
+    int nkb = 0;
+    int nbands = 0;
 
     int max_nh = 0;
     int max_npw = 0;
-    int ntype;
-    bool nondiagonal;
+    int ntype = 0;
+    bool nondiagonal = false;
     int pre_ik_s = -1;
     int pre_ik_f = -1;
 
diff --git a/source/source_pw/module_pwdft/nonlocal_maths.hpp b/source/source_pw/module_pwdft/nonlocal_maths.hpp
index 70d812e7c9..3e09675bcb 100644
--- a/source/source_pw/module_pwdft/nonlocal_maths.hpp
+++ b/source/source_pw/module_pwdft/nonlocal_maths.hpp
@@ -33,7 +33,7 @@ class Nonlocal_maths
 
   private:
     ModuleBase::matrix nhtol_;
-    int lmax_;
+    int lmax_ = 0;
     const UnitCell* ucell_;
 
     Device* ctx = {};
diff --git a/source/source_pw/module_pwdft/onsite_proj_tools.h b/source/source_pw/module_pwdft/onsite_proj_tools.h
index 2bfa5ebb44..de5a0cce43 100644
--- a/source/source_pw/module_pwdft/onsite_proj_tools.h
+++ b/source/source_pw/module_pwdft/onsite_proj_tools.h
@@ -104,8 +104,8 @@ class Onsite_Proj_tools
     Device* ctx = {};
     base_device::DEVICE_CPU* cpu_ctx = {};
     base_device::AbacusDevice_t device = {};
-    int nkb;
-    int nbands;
+    int nkb = 0;
+    int nbands = 0;
     int deeq_dims[4] = {0, 0, 0, 0};    // deeq can be something other than that in pseudopotentials
     int deeq_nc_dims[4] = {0, 0, 0, 0};
 
@@ -113,8 +113,8 @@ class Onsite_Proj_tools
 
     int max_nh = 0;
     int max_npw = 0;
-    int ntype;
-    bool nondiagonal;
+    int ntype = 0;
+    bool nondiagonal = false;
     int pre_ik_s = -1;
     int pre_ik_f = -1;
 
diff --git a/source/source_pw/module_pwdft/onsite_projector.cpp b/source/source_pw/module_pwdft/onsite_projector.cpp
index 4c03ce9b74..f9b8ad7cbc 100644
--- a/source/source_pw/module_pwdft/onsite_projector.cpp
+++ b/source/source_pw/module_pwdft/onsite_projector.cpp
@@ -503,7 +503,7 @@ void projectors::OnsiteProjector<T, Device>::read_abacus_orb(std::ifstream& ifs,
     {
         if (rank == 0)
         {
-            int l, izeta;
+            int l = 0, izeta = 0;
             ifs >> tmp >> tmp >> tmp;
             ifs >> tmp >> l >> izeta;
             ichi = radial_map_[l][izeta];
diff --git a/source/source_pw/module_pwdft/op_pw_exx_ace.cpp b/source/source_pw/module_pwdft/op_pw_exx_ace.cpp
index d6c7f6517d..3fdef6cb00 100644
--- a/source/source_pw/module_pwdft/op_pw_exx_ace.cpp
+++ b/source/source_pw/module_pwdft/op_pw_exx_ace.cpp
@@ -149,7 +149,7 @@ void OperatorEXXPW<T, Device>::construct_ace() const
                 for (int iq0 = 0; iq0 < nqs; iq0++)
                 {
                     // For nspin=2, iq should be in the same spin channel as ik
-                    int iq;
+                    int iq = 0;
 
                     int nk = wfcpw->nks / 2;
                     iq = iq0 + ispin * nk; // iq in the same spin channel
diff --git a/source/source_pw/module_pwdft/parallel_grid.cpp b/source/source_pw/module_pwdft/parallel_grid.cpp
index 73cbba225e..ff20f40d73 100644
--- a/source/source_pw/module_pwdft/parallel_grid.cpp
+++ b/source/source_pw/module_pwdft/parallel_grid.cpp
@@ -90,7 +90,7 @@ void Parallel_Grid::init(const int& ncx_in,
     assert(GlobalV::KPAR > 0);
 
     this->nproc_in_pool = new int[GlobalV::KPAR];
-    int nprocgroup;
+    int nprocgroup = 0;
     if (PARAM.inp.esolver_type == "sdft")
     {
         nprocgroup = GlobalV::NPROC_IN_BNDGROUP;
diff --git a/source/source_pw/module_pwdft/soc.cpp b/source/source_pw/module_pwdft/soc.cpp
index d90b334a2f..a44a0b6a48 100644
--- a/source/source_pw/module_pwdft/soc.cpp
+++ b/source/source_pw/module_pwdft/soc.cpp
@@ -122,7 +122,7 @@ int Soc::sph_ind(const int l, const double j, const int m, const int spin)
     // in a spinor with orbital angular momentum l, total angular
     // momentum j, projection along z of the total angular momentum m+-1/2.
     // Spin selects the up (spin=1) or down (spin=2) coefficient.
-    int sph_ind0;
+    int sph_ind0 = 0;
     if (spin != 0 && spin != 1)
     {
         ModuleBase::WARNING_QUIT("sph_ind", "spin must be 0 1");
diff --git a/source/source_pw/module_pwdft/stress_loc.cpp b/source/source_pw/module_pwdft/stress_loc.cpp
index 11c414f4dc..0b932afcdb 100644
--- a/source/source_pw/module_pwdft/stress_loc.cpp
+++ b/source/source_pw/module_pwdft/stress_loc.cpp
@@ -188,7 +188,7 @@ const UnitCell& ucell_in
   //
 	
 
-	int igl0;
+	int igl0 = 0;
 	this->device = base_device::get_device_type<Device>(this->ctx);
 
 	std::vector<double> gx_arr(rho_basis->ngg+1);
@@ -276,7 +276,7 @@ void Stress_Func<FPTYPE, Device>::dvloc_coulomb(const UnitCell& ucell,
 												FPTYPE* dvloc, 
 												ModulePW::PW_Basis* rho_basis)
 {
-    int igl0;
+    int igl0 = 0;
 	// start from |G|=0 or not.
     if (rho_basis->gg_uniq[0] < 1.0e-8)
     {
diff --git a/source/source_pw/module_pwdft/vnl_pw.cpp b/source/source_pw/module_pwdft/vnl_pw.cpp
index 52d3d447da..73f17850e8 100644
--- a/source/source_pw/module_pwdft/vnl_pw.cpp
+++ b/source/source_pw/module_pwdft/vnl_pw.cpp
@@ -825,7 +825,7 @@ void pseudopot_cell_vnl::compute_qrad(UnitCell& cell)
                                     aux[ir] = besr[ir] * upf->qfuncl(l, ijv, ir);
                                 }
                                 // then we integrate with all the Q functions
-                                double vqint;
+                                double vqint = 0.0;
                                 ModuleBase::Integral::Simpson_Integral(kkbeta, aux, upf->rab.data(), vqint);
                                 qrad(it, l, ijv, iq) = vqint * pref;
                             }
@@ -1234,7 +1234,7 @@ void pseudopot_cell_vnl::init_vnl_alpha(const UnitCell& ucell) // pengfei Li 201
                         aux[ir] = ucell.atoms[it].ncpp.betar(ib, ir) * jl[ir]
                                   * ucell.atoms[it].ncpp.r[ir] * ucell.atoms[it].ncpp.r[ir];
                     }
-                    double vqint;
+                    double vqint = 0.0;
                     ModuleBase::Integral::Simpson_Integral(kkbeta, aux, ucell.atoms[it].ncpp.rab.data(), vqint);
                     this->tab_alpha(it, ib, L, iq) = vqint * pref;
                 }
diff --git a/source/source_pw/module_pwdft/vnl_pw_grad.cpp b/source/source_pw/module_pwdft/vnl_pw_grad.cpp
index eb70520f25..7e22df63bc 100644
--- a/source/source_pw/module_pwdft/vnl_pw_grad.cpp
+++ b/source/source_pw/module_pwdft/vnl_pw_grad.cpp
@@ -47,7 +47,7 @@ void pseudopot_cell_vnl::initgradq_vnl(const UnitCell &cell)
 					aux[ir] = cell.atoms[it].ncpp.betar(ib, ir) *
 					          djl[ir] * pow(cell.atoms[it].ncpp.r[ir],2);
 				} 
-				double vqint;
+				double vqint = 0.0;
 				ModuleBase::Integral::Simpson_Integral(kkbeta, aux, cell.atoms[it].ncpp.rab.data(), vqint);
 				this->tab_dq(it, ib, iq) = vqint * pref;
 			} 
diff --git a/source/source_pw/module_stodft/sto_forces.cpp b/source/source_pw/module_stodft/sto_forces.cpp
index 3fb761d85c..47a91f3dde 100644
--- a/source/source_pw/module_stodft/sto_forces.cpp
+++ b/source/source_pw/module_stodft/sto_forces.cpp
@@ -108,7 +108,7 @@ void Sto_Forces<FPTYPE, Device>::cal_stoforce(ModuleBase::matrix& force,
 
     if (ModuleSymmetry::Symmetry::symm_flag == 1)
     {
-        double d1, d2, d3;
+        double d1 = 0.0, d2 = 0.0, d3 = 0.0;
         for (int iat = 0; iat < ucell.nat; iat++)
         {
             ModuleBase::Mathzone::Cartesian_to_Direct(force(iat, 0),
diff --git a/source/source_pw/module_stodft/sto_iter.cpp b/source/source_pw/module_stodft/sto_iter.cpp
index cd00e2f6f2..99fd2ef2bb 100644
--- a/source/source_pw/module_stodft/sto_iter.cpp
+++ b/source/source_pw/module_stodft/sto_iter.cpp
@@ -273,7 +273,7 @@ void Stochastic_Iter<T, Device>::itermu(const int iter, elecstate::ElecState* pe
 {
     ModuleBase::TITLE("Stochastic_Iter", "itermu");
     ModuleBase::timer::tick("Stochastic_Iter", "itermu");
-    double dmu;
+    double dmu = 0.0;
     if (iter == 1)
     {
         dmu = 2;
@@ -294,8 +294,8 @@ void Stochastic_Iter<T, Device>::itermu(const int iter, elecstate::ElecState* pe
     double ne2 = calne(pes);
     double mu2 = this->stofunc.mu;
     double Dne = th_ne + 1;
-    double ne3;
-    double mu3;
+    double ne3 = 0.0;
+    double mu3 = 0.0;
 
     while (ne1 > targetne)
     {
@@ -440,7 +440,7 @@ double Stochastic_Iter<T, Device>::calne(elecstate::ElecState* pes)
     double totne = 0;
     KS_ne = 0;
     const int norder = p_che->norder;
-    double sto_ne;
+    double sto_ne = 0.0;
     if (this->method == 1)
     {
         // Note: spolyv contains kv.wk[ik]
diff --git a/source/source_pw/module_stodft/sto_iter.h b/source/source_pw/module_stodft/sto_iter.h
index 20837d708f..8a97796502 100644
--- a/source/source_pw/module_stodft/sto_iter.h
+++ b/source/source_pw/module_stodft/sto_iter.h
@@ -119,8 +119,8 @@ class Stochastic_Iter
     Sto_Func<double> stofunc;
     hamilt::HamiltSdftPW<T, Device>* p_hamilt_sto = nullptr;
 
-    double mu0; // chemical potential; unit in Ry
-    bool change;
+    double mu0 = 0.0; // chemical potential; unit in Ry
+    bool change = false;
     double targetne=0.0;
     Real* spolyv = nullptr;     //[Device] coefficients of Chebyshev expansion
     Real* spolyv_cpu = nullptr; //[CPU] coefficients of Chebyshev expansion
diff --git a/source/source_pw/module_stodft/sto_tool.h b/source/source_pw/module_stodft/sto_tool.h
index 65a8b792a0..6b0c9e2a59 100644
--- a/source/source_pw/module_stodft/sto_tool.h
+++ b/source/source_pw/module_stodft/sto_tool.h
@@ -53,8 +53,8 @@ struct parallel_distribution
         this->start = st_per;
         this->num_per = num_per;
     }
-    int start;
-    int num_per;
+    int start = 0;
+    int num_per = 0;
 };
 
 #ifdef __MPI
diff --git a/source/source_pw/module_stodft/sto_wf.cpp b/source/source_pw/module_stodft/sto_wf.cpp
index de9a4559e1..2ba8db2908 100644
--- a/source/source_pw/module_stodft/sto_wf.cpp
+++ b/source/source_pw/module_stodft/sto_wf.cpp
@@ -166,7 +166,7 @@ void Stochastic_WF<T, Device>::init_com_orbitals()
     const bool firstrankmore = false;
     const int npwx = this->npwx;
     const int nks = this->nks;
-    int igroup;
+    int igroup = 0;
     // former processor calculate more bands
     if (firstrankmore)
     {
@@ -219,7 +219,7 @@ void Stochastic_WF<T, Device>::init_com_orbitals()
         // give value to orbitals in one parallel group one by one.
         for (int ichi = 0; ichi < nchipk; ++ichi)
         {
-            int ig;
+            int ig = 0;
             if (igroup < re)
             {
                 // It has more nchip.
diff --git a/source/source_relax/ions_move_bfgs.cpp b/source/source_relax/ions_move_bfgs.cpp
index 9c52010862..ee8a9d97e9 100644
--- a/source/source_relax/ions_move_bfgs.cpp
+++ b/source/source_relax/ions_move_bfgs.cpp
@@ -144,7 +144,7 @@ void Ions_Move_BFGS::restart_bfgs(const double& lat0)
         std::ifstream hess_file("hess_in");
         if(hess_file)
         {
-            int rank1,rank2;
+            int rank1 = 0, rank2 = 0;
             hess_file >> rank1 >> rank2;
             if(rank1 == dim && rank2 == dim)
             {
diff --git a/source/source_relax/relax_sync.cpp b/source/source_relax/relax_sync.cpp
index 47f3e3b333..492feaea49 100644
--- a/source/source_relax/relax_sync.cpp
+++ b/source/source_relax/relax_sync.cpp
@@ -383,7 +383,7 @@ void Relax::perform_line_search()
     // perform line search
     bool restart_brent = false;
     double x = dmovel, y = etot;
-    double xnew, yd;
+    double xnew = 0.0, yd = 0.0;
 
     brent_done = this->ls.line_search(restart_brent, x, y, f, xnew, force_thr_eva);
     dmove = xnew;
@@ -497,7 +497,7 @@ void Relax::move_cell_ions(UnitCell& ucell, const bool is_new_dir)
     // or a line search step, the treatment is slightly different
     // and the input variable is_new_dir is used to make the distinction
 
-    double fac; // fac1 for force, fac2 for stress
+    double fac = 0.0; // fac1 for force, fac2 for stress
     if (is_new_dir)
     {
         fac = 1.0;
@@ -594,8 +594,7 @@ void Relax::move_cell_ions(UnitCell& ucell, const bool is_new_dir)
     // =================================================================
 
     // Calculating displacement in Cartesian coordinate (in Angstrom)
-    double move_ion[nat * 3];
-    ModuleBase::zeros(move_ion, nat * 3);
+    std::vector<double> move_ion(nat * 3, 0.0);
 
     for (int iat = 0; iat < nat; iat++)
     {
@@ -630,10 +629,10 @@ void Relax::move_cell_ions(UnitCell& ucell, const bool is_new_dir)
 
     if (ModuleSymmetry::Symmetry::symm_flag && ucell.symm.all_mbl && ucell.symm.nrotk > 0)
     {
-        ucell.symm.symmetrize_vec3_nat(move_ion);
+        ucell.symm.symmetrize_vec3_nat(move_ion.data());
     }
 
-    unitcell::update_pos_taud(ucell.lat,move_ion,ucell.ntype,ucell.nat,ucell.atoms);
+    unitcell::update_pos_taud(ucell.lat,move_ion.data(),ucell.ntype,ucell.nat,ucell.atoms);
 
     // Print the structure file.
     unitcell::print_tau(ucell.atoms,ucell.Coordinate,ucell.ntype,ucell.lat0,GlobalV::ofs_running);