diff --git a/en/command-line-flags.md b/en/command-line-flags.md
index d77bc7084..0efd46a5e 100644
--- a/en/command-line-flags.md
+++ b/en/command-line-flags.md
@@ -19,7 +19,7 @@ This document introduces DM's command-line flags.
 
 - The external address for communication between DM-master nodes
 - The default value is `"{peer-urls}"`
-- Optional flag. It can be in the form of `"domain-name:port"`
+- Optional flag. It can be in the form of `"http(s)://domain-name:port"`
 
 ### `--config`
 
diff --git a/zh/command-line-flags.md b/zh/command-line-flags.md
index f4cea41ba..1daf11322 100644
--- a/zh/command-line-flags.md
+++ b/zh/command-line-flags.md
@@ -20,7 +20,7 @@ aliases: ['/docs-cn/tidb-data-migration/dev/command-line-flags/']
 
 - DM-master 节点间通信的外部连接地址
 - 默认值为 `"{peer-urls}"`
-- 可选参数，可以为 `"域名:port"` 的形式
+- 可选参数，可以为 `"http(s)://域名:port"` 的形式
 
 ### `--config`