更新

app/Admin/Controllers/BannerController.php

@@ -64,7 +64,7 @@ class BannerController extends AdminController
             $form->display('id');
             $form->text('title');
             $form->image('img_url')->uniqueName()->removable(false);
-            $form->radio('site')->options(['1'=>'动态首页']);
+            $form->radio('site')->options(['1'=>'动态首页'])->default(1);
             $form->text('status');
 
             $form->display('created_at');