diff --git a/src/query/src/qFilter.c b/src/query/src/qFilter.c
index 51ac8654a61f977d609b01e24a0130f2a3366d0b..b3448daaaf1b873cf0739a2524f044519d3dfd5f 100644
--- a/src/query/src/qFilter.c
+++ b/src/query/src/qFilter.c
@@ -3178,8 +3178,8 @@ void filterJsonTypeConvert(SFilterInfo* info) {
   uint8_t type = 0;
   if(JSON_TYPE_NCHAR){ type = TSDB_DATA_TYPE_NCHAR;} else {type = TSDB_DATA_TYPE_BINARY;}
   for(int i = 0; i < info->unitNum; i++){
-    if(info->units[info->unitNum].compare.type == TSDB_DATA_TYPE_JSON){
-      info->units[info->unitNum].compare.type= type;
+    if(info->units[i].compare.type == TSDB_DATA_TYPE_JSON){
+      info->units[i].compare.type= type;
     }
   }