您必须更改path 以及URL 确保主题有效。我正在使用以下MU-Plugin 在我的一个本地设置中：

<?php
/* Plugin Name: Local Theme Roots */

if ( \'single.wp\' === $_SERVER[\'HTTP_HOST\'] )
    return;

add_filter( \'theme_root_uri\', \'t5_switch_theme_root\' );
add_filter( \'theme_root\',     \'t5_switch_theme_root\' );

/**
 * Create a custom theme directory.
 *
 * @wp-hook theme_root
 * @wp-hook theme_root_uri
 * @author  Thomas Scholz, http://toscho.de
 * @param   string $in URL or path
 * @return  string
 */
function t5_switch_theme_root( $in )
{
    // local multi-sites end with \'mu.wp\'. Example: t5.mu.wp.
    if ( 0 !== stripos( strrev( $_SERVER[\'HTTP_HOST\'] ), \'pw.um\' ) )
    {
        return $in;
    }


    if ( \'theme_root_uri\' === current_filter() )
    {
        return "http://themes.wp";
    }

    // If we made it so far we are in the \'theme_root\' filter.
    $new_root = dirname( dirname( __DIR__ ) ) . \'/wp-themes\';
    register_theme_directory( $new_root );
    return $new_root;
}