diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index 433a13cee65e55193dc15f54c5a47d7a12bd2883..88f50c6957250cbdc67b5759e56e0b1d0e78d2c2 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -6266,7 +6266,7 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     tVariantListItem* pItem = taosArrayGet(pVarList, 1);
     SSchema* pTagsSchema = tscGetTableColumnSchema(pTableMetaInfo->pTableMeta, columnIndex.columnIndex);
 
-    if (IS_VAR_DATA_TYPE(pTagsSchema->type) && (pItem->pVar.nLen > pTagsSchema->bytes * TSDB_NCHAR_SIZE)) {
+    if (IS_VAR_DATA_TYPE(pTagsSchema->type) && (pItem->pVar.nLen > pTagsSchema->bytes)) {
       return invalidOperationMsg(pMsg, msg14);
     }
 
@@ -6275,7 +6275,12 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
     }
 
     int32_t schemaLen = sizeof(STColumn) * numOfTags;
-    int32_t size = sizeof(SUpdateTableTagValMsg) + pTagsSchema->bytes + schemaLen + TSDB_EXTRA_PAYLOAD_SIZE;
+    int32_t size = 0;
+    if (pTagsSchema->type == TSDB_DATA_TYPE_JSON){
+      size = sizeof(SUpdateTableTagValMsg) + pTagsSchema->bytes + schemaLen + TSDB_EXTRA_PAYLOAD_SIZE;
+    } else {
+      size = sizeof(SUpdateTableTagValMsg) + TSDB_MAX_TAGS_LEN + schemaLen + TSDB_EXTRA_PAYLOAD_SIZE;
+    }
 
     if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, size)) {
       tscError("0x%"PRIx64" failed to malloc for alter table pMsg", pSql->self);
@@ -6306,15 +6311,37 @@ int32_t setAlterTableInfo(SSqlObj* pSql, struct SSqlInfo* pInfo) {
       d += sizeof(STColumn);
     }
 
-    // copy the tag value to pMsg body
-    if (tVariantDump(&pItem->pVar, pUpdateMsg->data + schemaLen, pTagsSchema->type, true)
-        != TSDB_CODE_SUCCESS){
-      return invalidOperationMsg(pMsg, msg13);
+    if (pTagsSchema->type == TSDB_DATA_TYPE_JSON){
+      SKVRowBuilder kvRowBuilder = {0};
+      if (tdInitKVRowBuilder(&kvRowBuilder) < 0) {
+        return TSDB_CODE_TSC_OUT_OF_MEMORY;
+      }
+      code = parseJsontoTagData(pItem->pVar.pz, &kvRowBuilder, pMsg, pTagsSchema->colId);
+      if (code != TSDB_CODE_SUCCESS) {
+        tdDestroyKVRowBuilder(&kvRowBuilder);
+        return code;
+      }
+      SKVRow row = tdGetKVRowFromBuilder(&kvRowBuilder);
+      tdDestroyKVRowBuilder(&kvRowBuilder);
+      if (row == NULL) {
+        return TSDB_CODE_TSC_OUT_OF_MEMORY;
+      }
+      tdSortKVRowByColIdx(row);
+      kvRowCpy(pUpdateMsg->data + schemaLen, row);
+      free(row);
+    }else{
+      // copy the tag value to pMsg body
+      if (tVariantDump(&pItem->pVar, pUpdateMsg->data + schemaLen, pTagsSchema->type, true)
+          != TSDB_CODE_SUCCESS){
+        return invalidOperationMsg(pMsg, msg13);
+      }
     }
 
     int32_t len = 0;
     if (!IS_VAR_DATA_TYPE(pTagsSchema->type)) {
       len = tDataTypes[pTagsSchema->type].bytes;
+    } else if(pTagsSchema->type == TSDB_DATA_TYPE_JSON){
+      len = kvRowLen(pUpdateMsg->data + schemaLen);
     } else {
       len = varDataTLen(pUpdateMsg->data + schemaLen);
       if(len > pTagsSchema->bytes) return invalidOperationMsg(pMsg, msg14);
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 9d523f273016e258940c67eaa1596153de0998eb..a8e7f9ca8136b4e0a7a7f86a54804c7b744c9833 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -1589,9 +1589,6 @@ int tscEstimateAlterTableMsgLength(SSqlCmd *pCmd) {
 }
 
 int tscBuildAlterTableMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
-  char *pMsg;
-  int   msgLen = 0;
-
   SSqlCmd    *pCmd = &pSql->cmd;
   SQueryInfo *pQueryInfo = tscGetQueryInfo(pCmd);
 
@@ -1620,14 +1617,7 @@ int tscBuildAlterTableMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
     pSchema++;
   }
 
-  pMsg = (char *)pSchema;
-  pAlterTableMsg->tagValLen = htonl(pAlterInfo->tagData.dataLen);
-  if (pAlterInfo->tagData.dataLen > 0) {
- 	 memcpy(pMsg, pAlterInfo->tagData.data, pAlterInfo->tagData.dataLen);
-  }
-  pMsg += pAlterInfo->tagData.dataLen;
-
-  msgLen = (int32_t)(pMsg - (char*)pAlterTableMsg);
+  int msgLen = sizeof(SAlterTableMsg) + sizeof(SSchema) * tscNumOfFields(pQueryInfo);
 
   pCmd->payloadLen = msgLen;
   pCmd->msgType = TSDB_MSG_TYPE_CM_ALTER_TABLE;