diff --git a/src/client/src/tscSystem.c b/src/client/src/tscSystem.c
index 19f275aa90fc348ae631499ca6b7c8c4091a75e7..63741e08f47316536743f8a8229c8a7cb6de1af0 100644
--- a/src/client/src/tscSystem.c
+++ b/src/client/src/tscSystem.c
@@ -440,30 +440,30 @@ int taos_options(TSDB_OPTION option, const void *arg, ...) {
 
 #include "cJSON.h"
 static setConfRet taos_set_config_imp(const char *config){
-  setConfRet ret;
+  setConfRet ret = {SET_CONF_RET_SUCC, {0}};
   static bool setConfFlag = false;
   if (setConfFlag) {
-    ret.retCode = -5;
+    ret.retCode = SET_CONF_RET_ERR_ONLY_ONCE;
     strcpy(ret.retMsg, "configuration can only set once");
     return ret;
   }
   taosInitGlobalCfg();
   cJSON *root = cJSON_Parse(config);
   if (root == NULL){
-    ret.retCode = -4;
+    ret.retCode = SET_CONF_RET_ERR_JSON_PARSE;
     strcpy(ret.retMsg, "parse json error");
     return ret;
   }
 
   int size = cJSON_GetArraySize(root);
   if(!cJSON_IsObject(root) || size == 0) {
-    ret.retCode = -3;
+    ret.retCode = SET_CONF_RET_ERR_JSON_INVALID;
     strcpy(ret.retMsg, "json content is invalid, must be not empty object");
     return ret;
   }
 
   if(size >= 1000) {
-    ret.retCode = -6;
+    ret.retCode = SET_CONF_RET_ERR_TOO_LONG;
     strcpy(ret.retMsg, "json object size is too long");
     return ret;
   }
@@ -471,21 +471,25 @@ static setConfRet taos_set_config_imp(const char *config){
   for(int i = 0; i < size; i++){
     cJSON *item = cJSON_GetArrayItem(root, i);
     if(!item) {
-      ret.retCode = -2;
+      ret.retCode = SET_CONF_RET_ERR_INNER;
       strcpy(ret.retMsg, "inner error");
       return ret;
     }
     if(!taosReadConfigOption(item->string, item->valuestring, NULL, NULL, TAOS_CFG_CSTATUS_OPTION, TSDB_CFG_CTYPE_B_CLIENT)){
-      ret.retCode = -1;
+      ret.retCode = SET_CONF_RET_ERR_PART;
       if (strlen(ret.retMsg) == 0){
-        snprintf(ret.retMsg, 1024, "part error|%s", item->string);
+        snprintf(ret.retMsg, RET_MSG_LENGTH - 1, "part error|%s", item->string);
       }else{
-        char tmp[1000] = {0};
-        strncpy(tmp, ret.retMsg, 1000);
-        snprintf(ret.retMsg, 1024, "%s|%s", tmp, item->string);
+        int leftSize = RET_MSG_LENGTH - 1 - strlen(ret.retMsg);
+        leftSize = leftSize >= 0 ? leftSize : 0;
+        strncat(ret.retMsg, "|",  leftSize);
+        leftSize = RET_MSG_LENGTH - 1 - strlen(ret.retMsg);
+        leftSize = leftSize >= 0 ? leftSize : 0;
+        strncat(ret.retMsg, item->string, leftSize);
       }
     }
   }
+  cJSON_Delete(root);
   setConfFlag = true;
   return ret;
 }
diff --git a/src/client/tests/setConfigTest.cpp b/src/client/tests/setConfigTest.cpp
index 1b3f74c1898d50b1912b05d35a94283ffdb1bafa..fb016715f6ad2f5311aa2d81b608c2043f86c4f0 100644
--- a/src/client/tests/setConfigTest.cpp
+++ b/src/client/tests/setConfigTest.cpp
@@ -62,3 +62,10 @@ TEST(testCase, set_config_test5) {
   ASSERT_EQ(ret.retCode, -3);
   printf("msg:%d->%s", ret.retCode, ret.retMsg);
 }
+
+TEST(testCase, set_config_test6) {
+  const char *config = "{\"numOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitThreadsnumOfCoitT3333dd\":\"10\", \"esdfa\":\"10\"}";
+  setConfRet ret = taos_set_config(config);
+  ASSERT_EQ(ret.retCode, -1);
+  printf("msg:%d->%s", ret.retCode, ret.retMsg);
+}
diff --git a/src/inc/taos.h b/src/inc/taos.h
index d77fa8f5fcb4c957c274d076a1d6f2ef5631c85a..662c66c6ec741b2e4c26977d7655985f1f5f8de2 100644
--- a/src/inc/taos.h
+++ b/src/inc/taos.h
@@ -62,9 +62,20 @@ typedef struct taosField {
   int16_t  bytes;
 } TAOS_FIELD;
 
+typedef enum {
+  SET_CONF_RET_SUCC = 0,
+  SET_CONF_RET_ERR_PART = -1,
+  SET_CONF_RET_ERR_INNER = -2,
+  SET_CONF_RET_ERR_JSON_INVALID = -3,
+  SET_CONF_RET_ERR_JSON_PARSE = -4,
+  SET_CONF_RET_ERR_ONLY_ONCE = -5,
+  SET_CONF_RET_ERR_TOO_LONG = -6
+} SET_CONF_RET_CODE;
+
+#define RET_MSG_LENGTH 1024
 typedef struct setConfRet {
-  char   retMsg[1024];
-  int8_t retCode;
+  SET_CONF_RET_CODE retCode;
+  char   retMsg[RET_MSG_LENGTH];
 } setConfRet;
 
 #ifdef _TD_GO_DLL_