$mailbody = '';
$mailtitle = "订单号:".$order_sn."支付成功！";
$mailbody .= "这里是提示信息";
$email='admin@qq.com';//改为要接收邮件的邮箱
$cfg_sendmail_bysmtp = 'Y';
$cfg_smtp_server = 'smtp.exmail.qq.com'; //qq邮件服务器地址  
$cfg_smtp_port = '25'; //端口号，默认为25
$cfg_smtp_usermail = 'mail@qq.com'; //发件邮箱地址
$cfg_smtp_user = 'dedecmsCMS无忧'; //名称
$cfg_webname = 'dedecmsCMS无忧'; //站名称  
$cfg_smtp_password = 'password'; //发件邮箱密码
$headers = "From:".$cfg_smtp_usermail."\r\nReply-To:".$cfg_smtp_usermail;
if($cfg_sendmail_bysmtp == 'Y' && !empty($cfg_smtp_server))
{
     $mailtype = 'TXT';
     require_once(dirname(__FILE__)."/../mail.class.php");
     $smtp = new smtp($cfg_smtp_server,$cfg_smtp_port,true,$cfg_smtp_usermail,$cfg_smtp_password);
     $smtp->debug = false;
     $smtp->sendmail($email,$cfg_webname,$cfg_smtp_usermail, $mailtitle, $mailbody, $mailtype);
}
else
{
     @mail($email, $mailtitle, $mailbody, $headers);
}