diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index f222266ee8ac3135f7e5b337b1a68bd87f20e4e8..4fc378dc2be9f75098c48fe1bae33b227149ca8f 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -1336,7 +1336,7 @@ static char *rand_bool_str(){
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_randbool_buff + (cursor * BOOL_BUFF_LEN);
+    return g_randbool_buff + ((cursor % MAX_PREPARED_RAND) * BOOL_BUFF_LEN);
 }
 
 static int32_t rand_bool(){
@@ -1351,7 +1351,8 @@ static char *rand_tinyint_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_randtinyint_buff + (cursor * TINYINT_BUFF_LEN);
+    return g_randtinyint_buff +
+        ((cursor % MAX_PREPARED_RAND) * TINYINT_BUFF_LEN);
 }
 
 static int32_t rand_tinyint()
@@ -1367,7 +1368,8 @@ static char *rand_smallint_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_randsmallint_buff + (cursor * SMALLINT_BUFF_LEN);
+    return g_randsmallint_buff +
+        ((cursor % MAX_PREPARED_RAND) * SMALLINT_BUFF_LEN);
 }
 
 static int32_t rand_smallint()
@@ -1383,7 +1385,7 @@ static char *rand_int_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_randint_buff + (cursor * INT_BUFF_LEN);
+    return g_randint_buff + ((cursor % MAX_PREPARED_RAND) * INT_BUFF_LEN);
 }
 
 static int32_t rand_int()
@@ -1399,7 +1401,8 @@ static char *rand_bigint_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_randbigint_buff + (cursor * BIGINT_BUFF_LEN);
+    return g_randbigint_buff +
+        ((cursor % MAX_PREPARED_RAND) * BIGINT_BUFF_LEN);
 }
 
 static int64_t rand_bigint()
@@ -1415,7 +1418,7 @@ static char *rand_float_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_randfloat_buff + (cursor * FLOAT_BUFF_LEN);
+    return g_randfloat_buff + ((cursor % MAX_PREPARED_RAND) * FLOAT_BUFF_LEN);
 }
 
 
@@ -1432,7 +1435,8 @@ static char *demo_current_float_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_rand_current_buff + (cursor * FLOAT_BUFF_LEN);
+    return g_rand_current_buff +
+        ((cursor % MAX_PREPARED_RAND) * FLOAT_BUFF_LEN);
 }
 
 static float UNUSED_FUNC demo_current_float()
@@ -1449,7 +1453,8 @@ static char *demo_voltage_int_str()
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_rand_voltage_buff + (cursor * INT_BUFF_LEN);
+    return g_rand_voltage_buff +
+        ((cursor % MAX_PREPARED_RAND) * INT_BUFF_LEN);
 }
 
 static int32_t UNUSED_FUNC demo_voltage_int()
@@ -1464,7 +1469,7 @@ static char *demo_phase_float_str() {
     static int cursor;
     cursor++;
     if (cursor > (MAX_PREPARED_RAND - 1)) cursor = 0;
-    return g_rand_phase_buff + (cursor * FLOAT_BUFF_LEN);
+    return g_rand_phase_buff + ((cursor % MAX_PREPARED_RAND) * FLOAT_BUFF_LEN);
 }
 
 static float UNUSED_FUNC demo_phase_float(){
@@ -5199,7 +5204,8 @@ static int64_t generateStbRowData(
                         "SMALLINT", 8)) {
                 tmp = rand_smallint_str();
                 tmpLen = strlen(tmp);
-                tstrncpy(pstr + dataLen, tmp, min(tmpLen + 1, SMALLINT_BUFF_LEN));
+                tstrncpy(pstr + dataLen, tmp,
+                        min(tmpLen + 1, SMALLINT_BUFF_LEN));
             }  else if (0 == strncasecmp(stbInfo->columns[i].dataType,
                         "TINYINT", 7)) {
                 tmp = rand_tinyint_str();
@@ -5212,9 +5218,9 @@ static int64_t generateStbRowData(
                 tstrncpy(pstr + dataLen, tmp, min(tmpLen +1, BOOL_BUFF_LEN));
             }  else if (0 == strncasecmp(stbInfo->columns[i].dataType,
                         "TIMESTAMP", 9)) {
-                tmp = rand_int_str();
+                tmp = rand_bigint_str();
                 tmpLen = strlen(tmp);
-                tstrncpy(pstr + dataLen, tmp, min(tmpLen +1, INT_BUFF_LEN));
+                tstrncpy(pstr + dataLen, tmp, min(tmpLen +1, BIGINT_BUFF_LEN));
             }  else {
                 errorPrint( "Not support data type: %s\n",
                         stbInfo->columns[i].dataType);