Blockquote /app/design/frontend/default/default/layout/catalog.xml

打开此Xml文件并粘贴此代码.

<reference name="left">
            <block type="catalog/navigation" name="catalog.leftnav" template="catalog/navigation/left_nav.phtml" />
</reference>

进一步打开这个文件..

/app/design/frontend/default/default/template/catalog/navigation/left_nav.phtml

粘贴此代码：

 <?php
$obj = new Mage_Catalog_Block_Navigation();
$store_cats = $obj->getStoreCategories();
$current_cat    = $obj->getCurrentCategory();
$current_cat    = (is_object($current_cat) ? $current_cat->getName() : '');

foreach ($store_cats as $cat) {
    if ($cat->getName() == $current_cat) {
        echo '<li class="current"><a href="'.$this->getCategoryUrl($cat).'">'.$cat->getName()."</a>\n<ul>\n";
        foreach ($obj->getCurrentChildCategories() as $subcat) {
            echo '<li><a href="'.$this->getCategoryUrl($subcat).'">'.$subcat->getName()."</a></li>\n";
        }
        echo "</ul>\n</li>\n";
    } else {
        echo '<li><a href="'.$this->getCategoryUrl($cat).'">'.$cat->getName()."</a></li>\n";
    }
}
?>