diff --git a/services/callback/send_action.go b/services/callback/send_action.go
index 555e181..07b8fc5 100644
--- a/services/callback/send_action.go
+++ b/services/callback/send_action.go
@@ -18,7 +18,7 @@ type SendActionRequest struct {
 	Oaid        string `position:"Query" field:"oaid" default:"" `
 	Ip          string `position:"Query" field:"ip" default:"" `
 	Ua          string `position:"Query" field:"ua" default:"" `
-	Os          int    `position:"Query" field:"Os" default:"" `
+	Os          int    `position:"Query" field:"os" default:"" `
 	ParamsArray []string
 }