最后，我自己找到了答案。

//add our action
add_action( \'save_post\', \'my_save_post\', 11, 2 );

function my_save_post($post_id, $post){

   //if it is just a revision don\'t worry about it
   if (wp_is_post_revision($post_id))
      return false;

   //if the post is an auto-draft we don\'t want to do anything either
   if($post->post_status != \'auto-draft\' ){

       // unhook this function so it doesn\'t loop infinitely
       remove_action(\'save_post\', \'my_save_post\' );

      //this is where it happens -- update the post and change the post_name/slug to the post_title
      wp_update_post(array(\'ID\' => $post_id, \'post_name\' => str_replace(\' \', \'-\', $_POST[\'post_title\'])));

      //re-hook this function
      add_action(\'save_post\', \'my_save_post\' );
   }
}

标题字段下面是slug字段。通常WordPress会根据您在标题字段中键入的内容自动创建一个slug。您所需要做的就是键入您想要的内容，然后发布。