diff --git a/rt-thread-version/rt-thread-standard/programming-manual/device/uart/uart_v2/uart.md b/rt-thread-version/rt-thread-standard/programming-manual/device/uart/uart_v2/uart.md
index 500ba63f00771ec79da5ca986206d579790947d7..489459f75f351843531bbe28883d8b1b0e2833e7 100644
--- a/rt-thread-version/rt-thread-standard/programming-manual/device/uart/uart_v2/uart.md
+++ b/rt-thread-version/rt-thread-standard/programming-manual/device/uart/uart_v2/uart.md
@@ -608,7 +608,7 @@ static rt_err_t uart_input(rt_device_t dev, rt_size_t size)
     msg.size = size;
 
     result = rt_mq_send(&rx_mq, &msg, sizeof(msg));
-    if (result == -RT_EFULL)
+    if (result == RT_EFULL)
     {
         /* 消息队列满 */
         rt_kprintf("message queue full！\n");