diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 22189dd0be7989ceb855f042fffcf5d0ee2f4c51..0204282fcc75e0b1a6a7eac2ea9e1249a226669f 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -4588,7 +4588,7 @@ int32_t tscGetColFilterSerializeLen(SQueryInfo* pQueryInfo) {
     for (int32_t j = 0; j < pCol->info.flist.numOfFilters; ++j) {
       len += sizeof(SColumnFilterInfo);
       if (pCol->info.flist.filterInfo[j].filterstr) {
-        len += pCol->info.flist.filterInfo[j].len + 1 * TSDB_NCHAR_SIZE;
+        len += (int32_t)pCol->info.flist.filterInfo[j].len + 1 * TSDB_NCHAR_SIZE;
       }
     }
   }