diff --git a/components/net/at/src/at_client.c b/components/net/at/src/at_client.c
index a613ea1435edb1eef146710e9887a2a5efaa1032..b320072b00fb8e4be358103faec6f245a2637a1b 100644
--- a/components/net/at/src/at_client.c
+++ b/components/net/at/src/at_client.c
@@ -735,6 +735,8 @@ static void client_parser(at_client_t client)
             {
                 at_response_t resp = client->resp;
 
+                char end_ch = client->recv_line_buf[client->recv_line_len - 1];
+
                 /* current receive is response */
                 client->recv_line_buf[client->recv_line_len - 1] = '\0';
                 if (resp->buf_len + client->recv_line_len < resp->buf_size)
@@ -752,7 +754,12 @@ static void client_parser(at_client_t client)
                     LOG_E("Read response buffer failed. The Response buffer size is out of buffer size(%d)!", resp->buf_size);
                 }
                 /* check response result */
-                if (rt_memcmp(client->recv_line_buf, AT_RESP_END_OK, rt_strlen(AT_RESP_END_OK)) == 0
+                if ((client->end_sign != 0) && (end_ch == client->end_sign) && (resp->line_num == 0))
+                {
+                    /* get the end sign, return response state END_OK.*/
+                    client->resp_status = AT_RESP_OK;
+                }
+                else if (rt_memcmp(client->recv_line_buf, AT_RESP_END_OK, rt_strlen(AT_RESP_END_OK)) == 0
                         && resp->line_num == 0)
                 {
                     /* get the end data by response result, return response state END_OK. */
diff --git a/components/net/at/src/at_utils.c b/components/net/at/src/at_utils.c
index 8d8887fe5e1ace524a7953a7b8ed0897e49f78ac..d75ee0990e4c71fa3bba8aa9bc8b9cf3d78af96b 100644
--- a/components/net/at/src/at_utils.c
+++ b/components/net/at/src/at_utils.c
@@ -68,21 +68,30 @@ const char *at_get_last_cmd(rt_size_t *cmd_size)
 rt_size_t at_vprintf(rt_device_t device, const char *format, va_list args)
 {
     last_cmd_len = vsnprintf(send_buf, sizeof(send_buf), format, args);
+    if(last_cmd_len > sizeof(send_buf))
+        last_cmd_len = sizeof(send_buf);
 
 #ifdef AT_PRINT_RAW_CMD
     at_print_raw_cmd("sendline", send_buf, last_cmd_len);
 #endif
 
-    return rt_device_write(device, 0, send_buf, last_cmd_len);
+    return at_device_send(device, 0, send_buf, last_cmd_len);
 }
 
 rt_size_t at_vprintfln(rt_device_t device, const char *format, va_list args)
 {
     rt_size_t len;
 
-    len = at_vprintf(device, format, args);
+    last_cmd_len = vsnprintf(send_buf, sizeof(send_buf) - 2, format, args);
+    if(last_cmd_len > sizeof(send_buf) - 2)
+        last_cmd_len = sizeof(send_buf) - 2;
+    rt_memcpy(send_buf + last_cmd_len, "\r\n", 2);
 
-    rt_device_write(device, 0, "\r\n", 2);
+    len = last_cmd_len + 2;
 
-    return len + 2;
+#ifdef AT_PRINT_RAW_CMD
+    at_print_raw_cmd("sendline", send_buf, len);
+#endif
+
+    return at_device_send(device, 0, send_buf, len);
 }