diff --git a/tunnel-server/README.md b/tunnel-server/README.md
index 76016d443..b0cacbbb1 100644
--- a/tunnel-server/README.md
+++ b/tunnel-server/README.md
@@ -1,5 +1,3 @@
-
-
 ## How it works
 
 Tunnel server/client use websocket protocol.
@@ -8,24 +6,36 @@ For example:
 
 1. Arthas tunnel server listen at `192.168.1.10:7777`
 
-1. Arthas tunnel client register to the tunnel server
+2. Arthas tunnel client register to the tunnel server
+
+   tunnel client connect to tunnel server with URL: `ws://192.168.1.10:7777/ws?method=agentRegister`
 
-    tunnel client connect to tunnel server with URL: `ws://192.168.1.10:7777/ws?method=agentRegister`
+   tunnel server response a text frame message: `response:/?method=agentRegister&id=bvDOe8XbTM2pQWjF4cfw`
 
-    tunnel server response a text frame message: `response:/?method=agentRegister&id=bvDOe8XbTM2pQWjF4cfw`
+   This connection is `control connection`.
 
-    This connection is `control connection`.
+3. The browser try connect to remote arthas agent
 
-1. The browser try connect to remote arthas agent, start connect to tunnel server with URL: `'ws://192.168.1.10:7777/ws?method=connectArthas&id=bvDOe8XbTM2pQWjF4cfw`
+   start connect to tunnel server with URL: `'ws://192.168.1.10:7777/ws?method=connectArthas&id=bvDOe8XbTM2pQWjF4cfw`
 
-1. Arthas server find the `control connection` with the id `bvDOe8XbTM2pQWjF4cfw`, then send a text frame to arthas client: `response:/?method=startTunnel&id=bvDOe8XbTM2pQWjF4cfw&clientConnectionId=AMku9EFz2gxeL2gedGOC`
+4. Arthas server find the `control connection` with the id `bvDOe8XbTM2pQWjF4cfw`
+   
+   then send a text frame to arthas client: `response:/?method=startTunnel&id=bvDOe8XbTM2pQWjF4cfw&clientConnectionId=AMku9EFz2gxeL2gedGOC`
 
-1. Arhtas tunnel client open a new connection to tunnel server, URL: `ws://127.0.0.1:7777/ws/?method=openTunnel&clientConnectionId=AMku9EFz2gxeL2gedGOC&id=bvDOe8XbTM2pQWjF4cfw`. This connection is `tunnel connection`.
+5. Arthas tunnel client open a new connection to tunnel server
 
-1. Arhtas tunnel client start connect to local arthas agent, URL: `ws://127.0.0.1:3658/ws`. This connection is `local connection`.
+   URL: `ws://127.0.0.1:7777/ws/?method=openTunnel&clientConnectionId=AMku9EFz2gxeL2gedGOC&id=bvDOe8XbTM2pQWjF4cfw`
+   
+   This connection is `tunnel connection`
 
-1. Forward websocket frame between `tunnel connection` and `local connection`.
+6. Arthas tunnel client start connect to local arthas agent, URL: `ws://127.0.0.1:3658/ws`
 
+   This connection is `local connection`
+
+7. Forward websocket frame between `tunnel connection` and `local connection`.
+
+```
++---------+     +----------------------+       +----------------------+     +--------------+
+| browser <-----> arthas tunnel server | <-----> arthas tunnel client <--- -> arthas agent |
+|---------+     +----------------------+       +----------------------+     +--------------+
 ```
-browser <-> arthas tunnel server <-> arthas tunnel client <-> arthas agent
-```
\ No newline at end of file