首先找到文件：/source/class/class_core.php

将下列代码找到：
$_G['siteurl'] = htmlspecialchars('http://'.$_SERVER['HTTP_HOST'].$sitepath.'/');
$url = parse_url($_G['siteurl']);
$_G['siteroot'] = isset($url['path']) ? $url['path'] : '';
改为：
$_G['siteurl'] = str_replace("/子目录名/","",htmlspecialchars('http://'.$_SERVER['HTTP_HOST'].preg_replace("/\/+(api)?\/*$/i","",substr($_G['PHP_SELF'], 0, strrpos($_G['PHP_SELF'], '/'))).'/'));
$_G['siteroot'] = str_replace("/子目录名/","",substr($_G['PHP_SELF'], 0, -strlen($_G['basefilename']))); //注意在子目录名后面千万不要加"/"

遗留问题Discuz! Board's Archiver 路径还是不正确