diff --git a/docs/api/dialog.md b/docs/api/dialog.md
index 14960f3f194..a0e29f4fd9a 100644
--- a/docs/api/dialog.md
+++ b/docs/api/dialog.md
@@ -76,6 +76,7 @@ would be passed via `callback(filename)`
   * `title` String - Title of the message box, some platforms will not show it
   * `message` String - Content of the message box
   * `detail` String - Extra information of the message
+  * `icon` [Image](image.md)
 * `callback` Function
 
 Shows a message box, it will block until the message box is closed. It returns