diff --git a/rt-thread-version/rt-thread-standard/programming-manual/at/at.md b/rt-thread-version/rt-thread-standard/programming-manual/at/at.md
index f0224959e1fced9c99340b29b8a24386538f5281..3012a5d9fd768bc67faef78a759561016b8f991d 100644
--- a/rt-thread-version/rt-thread-standard/programming-manual/at/at.md
+++ b/rt-thread-version/rt-thread-standard/programming-manual/at/at.md
@@ -482,7 +482,7 @@ rt_err_t at_exec_cmd(at_response_t resp, const char *cmd_expr, ...);
 #include <rtthread.h>
 #include <at.h>   /* AT 组件头文件 */
 
-int at_client_send(int argc, char**argv)
+int at_Client_send(int argc, char**argv)
 {
     at_response_t resp = RT_NULL;
 
@@ -504,7 +504,7 @@ int at_client_send(int argc, char**argv)
     if (at_exec_cmd(resp, argv[1]) != RT_EOK)
     {
         LOG_E("AT client send commands failed, response error or timeout !");
-        return -ET_ERROR;
+        return -RT_ERROR;
     }
 
     /* 命令发送成功 */