我会把它挂上publish_post, 这样你就不会弄乱草稿等了。

你需要考虑多个类别，计算每个类别中的帖子数量，删除超过10个的帖子。

也许这样的事情会让你走上正确的方向。可能需要一些调整，大部分未经测试。

function on_post_publish( $ID, $post ) {

    $cat = get_the_category( $ID ); //returns array of categories

    foreach ($cat as $c) {    //doing the rest for each cat in array
        $args = array(
                    \'orderby\'  => \'post_date\',   //using the post date to order them
                    \'order\'     => \'ASC\',       // putting oldest at first key
                    \'cat\'       => $c,          // only of the current cat
                    \'posts_per_page\'  => -1,   //give us all of them
                    \'fields\' => \'ids\'         //only give us ids, we dont want whole objects
            );
       $query = new WP_Query( $args );

       $count = $query->post_count;         //get the WP_Queries post_count object value

       if ($count > 10) {                         // if that value is more than 10
            $id_to_delete = $query->posts[0];    //get oldest post from query
            wp_delete_post( $id_to_delete );    //delete it
       }


    }
    wp_reset_postdata(); //resetting to main query just in case


}

add_action(  \'publish_post\',  \'on_post_publish\', 10, 2 );