require 'app/Mage.php';

if (!Mage::isInstalled()) {
    echo "Application is not installed yet, please complete install wizard first.";
    exit;
}


Mage::app()->getCacheInstance()->flush();
echo 'Flushed cache successfully';

把代码保存在网站根目录下，通过浏览器访问则可快速清空magento站点缓存