你可以用钩子做这样的事pre_post_update :

function wpse_108013_mandatory_featured_image() {
 if(!has_post_thumbnail()) { // here you check if there\'s a featured image
      wp_die( \'Featured image must always be set !\' ); // there is no featured image
 } 
}
add_action( \'pre_post_update\', \'wpse_108013_mandatory_featured_image\' );