header(‘Content-type:text‘);
define("TOKEN", "weixin");

$signature = $_GET[‘signature‘];//微信待验证参数
$timestamp = $_GET[‘timestamp‘];//时间戳
$nonce = $_GET[‘nonce‘];//随机数
$token = TOKEN;//token 公众号后台配置的
$tmpArr = array($timestamp,$nonce,$token);
sort($tmpArr);
$tmpStr = implode($tmpArr);
$tmpStr = sha1($tmpStr);
if($tmpStr == $signature){//验证
    echo $_GET[‘echostr‘];//记得 输出该参数
}else{
    return false;
}