function related_posts_shortcode( $atts, $content = null ) {
     //extract the shortcode atts and set default
     extract( shortcode_atts( array(
         \'cat\' => \'\',
         \'limit\' => 4
     ), $atts ) );

     //store the current post ID so we don\'t display it as featured
     $post_ID = get_the_ID();

     //set up our args for the query
     $args = array(
         \'cat\' => $cat,
         \'posts_per_page\' => $limit
     );

     $html = \'\';
     $i = 0;

     //query for our posts
     $posts = new WP_Query( $args );

     //if we have posts, loop them
     if( $posts->have_posts() ): while( $posts->have_posts() ): $posts->the_post();
         //check to make sure not the same post as main post
         if ( $post_ID != get_the_ID() )
             //if post has thumbnail display it with link to post
             if ( has_post_thumbnail( get_the_ID() ) ) {
                 $html .= \'<a href="\' . get_the_permalink(); . \'">\';
                     $html .= get_the_post_thumbnail( get_the_ID() );
                 $html .= \'</a>\';
             }
             $html .= \'<a href="\' . get_the_permalink(); . \'">\';
                $html .= \'<h2>\' . get_the_title() . \'</h2>\'; //set link on title and display it
             $html .= \'</a>\';
             ++$i;
         }

         //if $i == 2 ( $limit default - 2 ) we have three posts so break, change for more posts, i just went off of your image example
         if ( $i == $limit - 2 ) break;
     endwhile;
     endif;

     //even though WP_Query doesn\'t effect the main loop, reset it as precaution
     wp_reset_query();

     //return generated html for recent posts
     return $html;
}

add_shortcode( \'related_posts\', \'related_posts_shortcode\' );

将以下代码添加到函数中。php文件，然后在帖子中可以执行以下操作：[related_posts cat="6" limit="4"/] cat是你想要的帖子类别，limit是你想要的相关帖子数量（+1）：加1的原因是因为你不想返回当前帖子，所以我们会多留一个，以防我们在循环中碰到当前帖子。你也可以在任何帖子中使用这个。如果要在模板中使用它，只需执行以下操作：<?php do_shortcode("[related_posts cat=\'6\' limit=\'4\'/]"); ?>
希望这对您有所帮助！