diff --git a/doc/API.md b/doc/API.md
index db47d93..33e90b3 100644
--- a/doc/API.md
+++ b/doc/API.md
@@ -12,7 +12,7 @@ rtm 包提供go连接和访问 RTM 后端服务的能力。
 
 ## Constants
 
-	const SDKVersion = "0.3.1"
+	const SDKVersion = "0.4.0"
 
 ## Variables