唷！比我想象的要复杂一点-只要过滤器page_css_class 传回$args 这将节省大量工作（可能会将此提交给trac）

Since 3.3 就这么简单！

function add_parent_class( $css_class, $page, $depth, $args )
{
    if ( ! empty( $args[\'has_children\'] ) )
        $css_class[] = \'parent\';
    return $css_class;
}
add_filter( \'page_css_class\', \'add_parent_class\', 10, 4 );

/**
 * Extend the default page walker class to append class names for pages that
 * are parents.
 * @uses Walker_Page
 */ 
class My_Page_Walker extends Walker_Page
{
    /**
     * Filter in the classes for parents.
     */
    function _filterClass( $class )
    {
        $class[] = \'parent\'; // change this to whatever classe(s) you require
        return $class;
    }

    /**
     * This is effectively a wrapper for the default method, dynamically adding
     * and removing the class filter when the current item has children.
     */
    function start_el( &$output, $page, $depth, $args, $current_page )
    {
        if ( !empty($args[\'has_children\']) )
            add_filter( \'page_css_class\', array( &$this, \'_filterClass\') );

        parent::start_el( $output, $page, $depth, $args, $current_page );

        if ( !empty($args[\'has_children\']) )
            remove_filter( \'page_css_class\', array( &$this, \'_filterClass\') );
    }
}

要使用它，请致电wp_list_pages() 像这样；

// You need to pass the walker argument to wp_list_pages(). You must use an
// array to do this.
wp_list_pages(array(
    \'walker\'   => new My_Page_Walker,
    \'title_li\' => \'\'
));