diff --git a/be/src/vec/functions/function_string.h b/be/src/vec/functions/function_string.h
index 57640ed3c866ed..c48f42022e7b2a 100644
--- a/be/src/vec/functions/function_string.h
+++ b/be/src/vec/functions/function_string.h
@@ -3279,7 +3279,7 @@ class FunctionIntToChar : public IFunction {
     void integer_to_char_(int line_num, const int* num, ColumnString::Chars& chars,
                           IColumn::Offsets& offsets) {
         if (0 == *num) {
-            chars.push_back(' ');
+            chars.push_back('\0');
             offsets[line_num] = offsets[line_num - 1] + 1;
             return;
         }
@@ -3293,7 +3293,7 @@ class FunctionIntToChar : public IFunction {
         }
         offsets[line_num] = offsets[line_num - 1] + k + 1;
         for (; k >= 0; --k) {
-            chars.push_back(bytes[k] ? bytes[k] : ' ');
+            chars.push_back(bytes[k] ? bytes[k] : '\0');
         }
 #else
         int k = 0;
@@ -3304,7 +3304,7 @@ class FunctionIntToChar : public IFunction {
         }
         offsets[line_num] = offsets[line_num - 1] + 4 - k;
         for (; k < 4; ++k) {
-            chars.push_back(bytes[k] ? bytes[k] : ' ');
+            chars.push_back(bytes[k] ? bytes[k] : '\0');
         }
 #endif
     }
diff --git a/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out b/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out
index b51fb32d6150ec..118c58c491081b 100644
Binary files a/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out and b/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out differ
diff --git a/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy b/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy
index 6a069923226ccf..a729e179b09bac 100644
--- a/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy
+++ b/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy
@@ -280,5 +280,7 @@ suite("test_string_function") {
     qt_sql_func_char6 """ select char(k1) from test_function_char order by k1; """
     qt_sql_func_char7 """ select char(k1, k2, k3, k4) from test_function_char order by k1, k2, k3, k4; """
     qt_sql_func_char8 """ select char(k1, k2, k3, k4, 65) from test_function_char order by k1, k2, k3, k4; """
+    qt_sql_func_char9 """ select char(0) = ' '; """
+    qt_sql_func_char10 """ select char(0) = '\0'; """
 
 }