diff --git a/paramset.go b/paramset.go
index 609eb95..201ac58 100644
--- a/paramset.go
+++ b/paramset.go
@@ -44,7 +44,7 @@ func (m *MessageCenter) getAccessToken() (string, error) {
 	if tokenInstance, exist := cache.InstanceCacheMap().Get(m.ClientKey); exist {
 		data = tokenInstance.(accessTokenResponse)
 		if int64(data.AccessExpire) >= time.Now().Unix() {
-			return tokenInstance.(string), nil
+			return data.AccessToken, nil
 		}
 	}
 	var authParam, _ = json.Marshal(map[string]string{"client_key": m.ClientKey, "client_secret": m.ClientSecret})