diff --git a/be/src/exprs/aggregate_functions.cpp b/be/src/exprs/aggregate_functions.cpp
index 9086a5773696ab..b27637f8c971b8 100644
--- a/be/src/exprs/aggregate_functions.cpp
+++ b/be/src/exprs/aggregate_functions.cpp
@@ -177,9 +177,10 @@ struct PercentileApproxState {
     PercentileApproxState() : digest(new TDigest()) {}
     PercentileApproxState(double compression) : digest(new TDigest(compression)) {}
     ~PercentileApproxState() { delete digest; }
+    static constexpr double INIT_QUANTILE  = -1.0;
 
     TDigest* digest = nullptr;
-    double targetQuantile = -1.0;
+    double targetQuantile = INIT_QUANTILE;
 };
 
 void AggregateFunctions::percentile_approx_init(FunctionContext* ctx, StringVal* dst) {
@@ -255,7 +256,12 @@ void AggregateFunctions::percentile_approx_merge(FunctionContext* ctx, const Str
 
     PercentileApproxState* dst_percentile = reinterpret_cast<PercentileApproxState*>(dst->ptr);
     dst_percentile->digest->merge(src_percentile->digest);
-    dst_percentile->targetQuantile = quantile;
+    // dst_percentile->targetQuantile only need set once from child result
+    // for example:
+    //    child result targetQuantile is (0.5, -1), we should set 0.5 once to make sure correct result
+    if (dst_percentile->targetQuantile == PercentileApproxState::INIT_QUANTILE) {
+        dst_percentile->targetQuantile = quantile;
+    }
 
     delete src_percentile;
 }
diff --git a/be/test/exprs/percentile_approx_test.cpp b/be/test/exprs/percentile_approx_test.cpp
index 8ed860b71fc16d..57a65359adb0fd 100644
--- a/be/test/exprs/percentile_approx_test.cpp
+++ b/be/test/exprs/percentile_approx_test.cpp
@@ -88,6 +88,26 @@ TEST_F(PercentileApproxTest, testSerialize) {
     AggregateFunctions::percentile_approx_merge(context, serialized, &stringVal2);
     DoubleVal v = AggregateFunctions::percentile_approx_finalize(context, stringVal2);
     ASSERT_DOUBLE_EQ(v.val, 99900.5);
+
+    // merge init percentile stringVal3 should not change the correct result
+    AggregateFunctions::percentile_approx_init(context, &stringVal);
+
+    for (int i = 1; i <= 100000; i++) {
+        DoubleVal val(i);
+        AggregateFunctions::percentile_approx_update(context, val, doubleQ, &stringVal);
+    }
+    serialized = AggregateFunctions::percentile_approx_serialize(context, stringVal);
+
+    StringVal stringVal3;
+    AggregateFunctions::percentile_approx_init(context, &stringVal2);
+    AggregateFunctions::percentile_approx_init(context, &stringVal3);
+    StringVal serialized2 = AggregateFunctions::percentile_approx_serialize(context, stringVal3);
+
+    AggregateFunctions::percentile_approx_merge(context, serialized, &stringVal2);
+    AggregateFunctions::percentile_approx_merge(context, serialized2, &stringVal2);
+    v = AggregateFunctions::percentile_approx_finalize(context, stringVal2);
+    ASSERT_DOUBLE_EQ(v.val, 99900.5);
+
     delete futil;
 }