可以使用php模数% 操作人员

让我们使用您的代码。

    <?php if ( have_posts() ) : ?>



        <?php twentyeleven_content_nav( \'nav-above\' ); ?>

        <?php /* Start the Loop */ ?>
        <?php $count = 1; ?>
        <?php while ( have_posts() ) : the_post(); ?>
        <?php
                /* Include the Post-Format-specific template for the content.
                 * If you want to overload this in a child theme then include a file
                 * called content-___.php (where ___ is the Post Format name) and that will be used instead.
                 */
                get_template_part( \'content\', get_post_format() );
            ?>

        <?php endwhile; ?>

然后在您的内容中。php：

    <?php
        global $count;
        if ($count % 3 === 0) {
            $no_margin = \'last\';
        }
    ?>    
    <div class="goods_list catalog_goods <?php echo $no_margin; ?>">
                    <div class="goods_item">
                      <div class="foto">
                        <div class="shadow"></div><?php the_excerpt(); ?>
                        <a href="<?php the_permalink(); ?>"><?php echo get_the_post_thumbnail($id,  array(220,220)); ?></a>
                      </div>
                      <div class="bot">
                       <a href="<?php the_permalink(); ?>" rel="bookmark"><?php the_title(); ?></a>

                        <div class="stars"></div>

                        <div class="order">
                          <a class="but_buy"><i class="icon-shopping-cart icon-large"></i> &nbsp;Buy </a>
                          <span class="price">$45.00</span>
                        </div>
                      </div>
                    </div>
                  </div>
<?php ++$count; ?>

这是主要部分

剩余的$count 除以3

并添加：

<div class="goods_list catalog_goods <?php echo $no_margin; ?>">

最后添加：

<?php ++$count; ?>