diff --git a/src/client/src/tscParseOpenTSDB.c b/src/client/src/tscParseOpenTSDB.c
index 6b34de63ffce3f4702ae0e9ed863ea02fb7a275b..2ec4eda772697b445615f73a529fb093885704a1 100644
--- a/src/client/src/tscParseOpenTSDB.c
+++ b/src/client/src/tscParseOpenTSDB.c
@@ -749,8 +749,17 @@ int32_t parseValueFromJSON(cJSON *root, TAOS_SML_KV *pVal, SSmlLinesInfo* info)
       break;
     }
     case cJSON_String: {
-      //convert default JSON String type to nchar
-      pVal->type = TSDB_DATA_TYPE_NCHAR;
+      /* set default JSON type to binary/nchar according to
+       * user configured parameter tsSmlDefaultJSONStrType
+       */
+      if (strcasecmp(tsSmlDefaultJSONStrType, "binary") == 0) {
+        pVal->type = TSDB_DATA_TYPE_BINARY;
+      } else if (strcasecmp(tsSmlDefaultJSONStrType, "nchar") == 0) {
+        pVal->type = TSDB_DATA_TYPE_NCHAR;
+      } else {
+        tscError("OTD:0x%"PRIx64" Invalid default JSON string type set from config %s", info->id, tsSmlDefaultJSONStrType);
+        return TSDB_CODE_TSC_INVALID_JSON_CONFIG;
+      }
       //pVal->length = wcslen((wchar_t *)root->valuestring) * TSDB_NCHAR_SIZE;
       pVal->length = (int16_t)strlen(root->valuestring);
       pVal->value = tcalloc(pVal->length + 1, 1);
diff --git a/src/common/inc/tglobal.h b/src/common/inc/tglobal.h
index 604ce89432bcf662b319fb2ec11f55026450a2be..e8d0937705f049bf3c1d4237eff4023a335ef611 100644
--- a/src/common/inc/tglobal.h
+++ b/src/common/inc/tglobal.h
@@ -216,7 +216,7 @@ extern int32_t cqDebugFlag;
 extern int32_t debugFlag;
 
 #ifdef TD_TSZ
-// lossy 
+// lossy
 extern char lossyColumns[];
 extern double fPrecision;
 extern double dPrecision;
@@ -224,9 +224,12 @@ extern uint32_t maxRange;
 extern uint32_t curRange;
 extern char Compressor[];
 #endif
-// long query 
+// long query
 extern int8_t tsDeadLockKillQuery;
 
+// schemaless
+extern char tsSmlDefaultJSONStrType[];
+
 typedef struct {
   char dir[TSDB_FILENAME_LEN];
   int  level;
diff --git a/src/common/src/tglobal.c b/src/common/src/tglobal.c
index 339fa35bb3009db96c9c6e0cabea6b60881f05c5..57a177b173e2b785064cb62668b7275c816e81fa 100644
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@@ -282,6 +282,9 @@ char     Compressor[32] = "ZSTD_COMPRESSOR"; // ZSTD_COMPRESSOR or GZIP_COMPRESS
 // long query death-lock
 int8_t tsDeadLockKillQuery = 0;
 
+// schemaless
+char tsSmlDefaultJSONStrType[7] = "binary";
+
 int32_t (*monStartSystemFp)() = NULL;
 void (*monStopSystemFp)() = NULL;
 void (*monExecuteSQLFp)(char *sql) = NULL;
@@ -1637,6 +1640,17 @@ static void doInitGlobalConfig(void) {
   cfg.unitType = TAOS_CFG_UTYPE_NONE;
   taosInitConfigOption(cfg);
 
+  // Schemaless config
+  cfg.option = "smlDefaultJSONStrType";
+  cfg.ptr = tsSmlDefaultJSONStrType;
+  cfg.valType = TAOS_CFG_VTYPE_STRING;
+  cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_SHOW | TSDB_CFG_CTYPE_B_CLIENT;
+  cfg.minValue = 0;
+  cfg.maxValue = 0;
+  cfg.ptrLength = tListLen(tsSmlDefaultJSONStrType);
+  cfg.unitType = TAOS_CFG_UTYPE_NONE;
+  taosInitConfigOption(cfg);
+
 #ifdef TD_TSZ
   // lossy compress
   cfg.option = "lossyColumns";
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index d59b88c7e698b3e965b5923efdc760e0289f7250..887c51f10c5a6c10e213bb893725a837a0be77cd 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -110,7 +110,8 @@ int32_t* taosGetErrno();
 #define TSDB_CODE_TSC_DUP_TAG_NAMES             TAOS_DEF_ERROR_CODE(0, 0x0220)  //"duplicated tag names")
 #define TSDB_CODE_TSC_INVALID_JSON              TAOS_DEF_ERROR_CODE(0, 0x0221)  //"Invalid JSON format")
 #define TSDB_CODE_TSC_INVALID_JSON_TYPE         TAOS_DEF_ERROR_CODE(0, 0x0222)  //"Invalid JSON data type")
-#define TSDB_CODE_TSC_VALUE_OUT_OF_RANGE        TAOS_DEF_ERROR_CODE(0, 0x0223)  //"Value out of range")
+#define TSDB_CODE_TSC_INVALID_JSON_CONFIG       TAOS_DEF_ERROR_CODE(0, 0x0223)  //"Invalid JSON configuration")
+#define TSDB_CODE_TSC_VALUE_OUT_OF_RANGE        TAOS_DEF_ERROR_CODE(0, 0x0224)  //"Value out of range")
 
 // mnode
 #define TSDB_CODE_MND_MSG_NOT_PROCESSED         TAOS_DEF_ERROR_CODE(0, 0x0300)  //"Message not processed")
diff --git a/src/util/inc/tconfig.h b/src/util/inc/tconfig.h
index cf8977ce06c898fcdee8d21eedf5ed8d0f47f263..97273e29fd4aa105c2eb64a90e22b90770afa69e 100644
--- a/src/util/inc/tconfig.h
+++ b/src/util/inc/tconfig.h
@@ -20,7 +20,7 @@
 extern "C" {
 #endif
 
-#define TSDB_CFG_MAX_NUM    123
+#define TSDB_CFG_MAX_NUM    124
 #define TSDB_CFG_PRINT_LEN  23
 #define TSDB_CFG_OPTION_LEN 24
 #define TSDB_CFG_VALUE_LEN  41
diff --git a/src/util/src/terror.c b/src/util/src/terror.c
index e3d022a6b0a4a929b6c06b2c305fb71b6980a865..404d4ad0c18944826abebf6d0e73c573dbe54756 100644
--- a/src/util/src/terror.c
+++ b/src/util/src/terror.c
@@ -118,6 +118,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_TSC_INVALID_COLUMN_LENGTH,    "Invalid column length
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_DUP_TAG_NAMES,            "duplicated tag names")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_INVALID_JSON,             "Invalid JSON format")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_INVALID_JSON_TYPE,        "Invalid JSON data type")
+TAOS_DEFINE_ERROR(TSDB_CODE_TSC_INVALID_JSON_CONFIG,      "Invalid JSON configuration")
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_VALUE_OUT_OF_RANGE,       "Value out of range")
 
 // mnode