diff --git a/be/src/vec/functions/function_conv.cpp b/be/src/vec/functions/function_conv.cpp
index c168c899006360..78abad9f342ecf 100644
--- a/be/src/vec/functions/function_conv.cpp
+++ b/be/src/vec/functions/function_conv.cpp
@@ -206,8 +206,12 @@ struct ConvStringImpl {
                                size_t index) {
         StringRef str = data_column->get_data_at(index);
         StringParser::ParseResult parse_res;
+        // select conv('ffffffffffffff', 24, 2);
+        // if 'ffffffffffffff' parse as int64_t will be overflow, will be get max value: std::numeric_limits<int64_t>::max()
+        // so change it parse as uint64_t, and return value could still use int64_t, in function decimal_to_base could handle it.
+        // But if the value is still overflow in uint64_t, will get max value of uint64_t
         int64_t decimal_num =
-                StringParser::string_to_int<int64_t>(str.data, str.size, src_base, &parse_res);
+                StringParser::string_to_int<uint64_t>(str.data, str.size, src_base, &parse_res);
         if (src_base < 0 && decimal_num >= 0) {
             result_null_map[index] = true;
             result_column->insert_default();
diff --git a/regression-test/data/nereids_p0/sql_functions/math_functions/test_conv.out b/regression-test/data/nereids_p0/sql_functions/math_functions/test_conv.out
index cb2f1e9d4a620e..e05c1a3437ae86 100644
--- a/regression-test/data/nereids_p0/sql_functions/math_functions/test_conv.out
+++ b/regression-test/data/nereids_p0/sql_functions/math_functions/test_conv.out
@@ -2,3 +2,12 @@
 -- !select --
 1111
 
+-- !select2 --
+1011111001100011011111100110111101001101111010011011110100110111
+
+-- !select3 --
+1111111111111111111111111111111111111111111111111111111010001001
+
+-- !select4 --
+18446744073709551615
+
diff --git a/regression-test/suites/nereids_p0/sql_functions/math_functions/test_conv.groovy b/regression-test/suites/nereids_p0/sql_functions/math_functions/test_conv.groovy
index 545bc8d6e75461..214e65ff4bdb16 100644
--- a/regression-test/suites/nereids_p0/sql_functions/math_functions/test_conv.groovy
+++ b/regression-test/suites/nereids_p0/sql_functions/math_functions/test_conv.groovy
@@ -19,5 +19,9 @@ suite("test_conv") {
     sql "SET enable_nereids_planner=true"
     sql "SET enable_fallback_to_original_planner=false"
     qt_select "SELECT CONV(15,10,2)"
+    qt_select2 "select conv('ffffffffffffff', 24, 2);"
+    qt_select3 "select conv('-ff', 24, 2);"
+    // if beyond the max value of uint64, use max_uint64 as res
+    qt_select4 "select conv('fffffffffffffffffffffffffffffffff', 24, 10);"
 }