你可以用这样的助行器，

class Walker_Recent_Post_Category extends Walker_Category {
    function start_el(&$output, $category, $depth, $args) { 
         extract($args); 

         $cat_name = esc_attr( $category->name); 
         $cat_name = apply_filters( \'list_cats\', $cat_name, $category ); 

         $list_recent_cat_post = \'<ul class="show-hide">\';
         $args = array( \'numberposts\' => 5, \'category_name\' => $category->name );
         $myposts = get_posts( $args );
         foreach( $myposts as $mypost ) :  
            $list_recent_cat_post .= \'<li><a href="\' . get_permalink($mypost->ID) . \'">\' . $mypost->post_title . \'</a></li>\';
         endforeach; 
         $list_recent_cat_post .= \'</ul>\';



         $link = \'<a href="\' . get_category_link( $category->term_id ) . \'" \'; 
         if ( $use_desc_for_title == 0 || empty($category->description) ) 
             $link .= \'title="\' . sprintf(__( \'View all posts filed under %s\' ), $cat_name) . \'"\'; 
         else 
             $link .= \'title="\' . esc_attr( strip_tags( apply_filters( \'category_description\', $category->description, $category ) ) ) . \'"\'; 
         $link .= \'>\'; 
         $link .= $cat_name . \'</a>\'; 

         if ( (! empty($feed_image)) || (! empty($feed)) ) { 
             $link .= \' \'; 

             if ( empty($feed_image) ) 
                 $link .= \'(\'; 

             $link .= \'<a href="\' . get_category_feed_link($category->term_id, $feed_type) . \'"\'; 

             if ( empty($feed) ) 
                 $alt = \' alt="\' . sprintf(__( \'Feed for all posts filed under %s\' ), $cat_name ) . \'"\'; 
             else { 
                 $title = \' title="\' . $feed . \'"\'; 
                 $alt = \' alt="\' . $feed . \'"\'; 
                 $name = $feed; 
                 $link .= $title; 
             } 

             $link .= \'>\'; 

             if ( empty($feed_image) ) 
                 $link .= $name; 
             else 
                 $link .= "<img src=\'$feed_image\'$alt$title" . \' />\'; 
             $link .= \'</a>\'; 
             if ( empty($feed_image) ) 
                 $link .= \')\'; 
         } 

         if ( isset($show_count) && $show_count ) 
             $link .= \' (\' . intval($category->count) . \')\'; 

         if ( isset($show_date) && $show_date ) { 
             $link .= \' \' . gmdate(\'Y-m-d\', $category->last_update_timestamp); 
         } 


         $link .= $list_recent_cat_post;


         if ( isset($current_category) && $current_category ) 
             $_current_category = get_category( $current_category ); 

         if ( \'list\' == $args[\'style\'] ) { 
             $output .= "\\t<li"; 
            $class = \'cat-item cat-item-\'.$category->term_id; 
             if ( isset($current_category) && $current_category && ($category->term_id == $current_category) ) 
                 $class .=  \' current-cat\'; 
             elseif ( isset($_current_category) && $_current_category && ($category->term_id == $_current_category->parent) ) 
                 $class .=  \' current-cat-parent\'; 
             $output .=  \' class="\'.$class.\'"\'; 
             $output .= ">$link\\n"; 
         } else { 
             $output .= "\\t$link\\n"; 
         } 
    }   
}

    <ul>
       <?php wp_list_categories(
                array(
                    \'show_count\'=>1,
                    \'title_li\'  =>\'\',
                    \'walker\'    => new Walker_Recent_Post_Category()
                )
             ); ?>
    </ul>

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