参见Wordpress codexhttp://codex.wordpress.org/Function_Reference/wp_nav_menu#How_to_add_a_parent_class_for_menu_item

使用此功能：

add_filter(\'wp_nav_menu_objects\', function ($items) {
    $hasSub = function ($menu_item_id, &$items) {
        foreach ($items as $item) {
            if ($item->menu_item_parent && $item->menu_item_parent==$menu_item_id) {
                return true;
            }
        }
        return false;
    };

    foreach ($items as &$item) {
        if ($hasSub($item->ID, &$items)) {
            $item->classes[] = \'menu-parent-item\'; // all elements of field "classes" of a menu item get join together and render to class attribute of 
 element in HTML
        }
    }
    return $items;    
});

您可以使用一点正则表达式和一个自定义菜单遍历器来实现这一点，尽管我尚未对此进行彻底测试：

class My_Walker_Nav_Menu extends Walker_Nav_Menu {
    function start_lvl(&$output, $depth) {
        $indent = str_repeat("\\t", $depth);
        $output = preg_replace( "/(.*)(\\<li.*?class\\=\\")([^\\"]*)(\\".*?)$/", "$1$2$3 has-submenu$4", $output );
        $output .= "\\n$indent<ul class=\\"sub-menu\\">\\n";
    }
}

要使用上述方法，只需传入walker参数，在其中声明菜单，例如：

wp_nav_menu( array( \'theme_location\' => \'header\', \'walker\' => new My_Walker_Nav_Menu() ) );