diff --git a/source/libs/scalar/src/sclfunc.c b/source/libs/scalar/src/sclfunc.c
index f2e50cb5c9..c1030f5da7 100644
--- a/source/libs/scalar/src/sclfunc.c
+++ b/source/libs/scalar/src/sclfunc.c
@@ -715,7 +715,8 @@ int32_t castFunction(SScalarParam *pInput, int32_t inputNum, SScalarParam *pOutp
           int32_t len = sprintf(varDataVal(output), "%.*s", (int32_t)(outputLen - VARSTR_HEADER_SIZE), *(int8_t *)input ? "true" : "false");
           varDataSetLen(output, len);
         } else if (inputType == TSDB_DATA_TYPE_BINARY) {
-          int32_t len = sprintf(varDataVal(output), "%.*s", (int32_t)(outputLen - VARSTR_HEADER_SIZE), varDataVal(input));
+          int32_t len = MIN(varDataLen(input), outputLen - VARSTR_HEADER_SIZE);
+          len = sprintf(varDataVal(output), "%.*s", len, varDataVal(input));
           varDataSetLen(output, len);
         } else if (inputType == TSDB_DATA_TYPE_NCHAR) {
           //not support