检查你的string.func.php

function verifyImage($type=1,$length=4,$pixel=50,$sess_name="verify")

    {

    //ͨ创建画布，定义黑色和白色

    $width = 80;

    $height =30;

    $image = imagecreatetruecolor($width, $height);

    $white = imagecolorallocate($image, 255, 255, 255);

    $black = imagecolorallocate($image, 0, 0, 0);

    //给画布添加白色背景

    imagefilledrectangle($image, 1, 1, $width-2, $height-2, $white);

    $chars=buildRandomString($type,$length);   

    $_SESSION[$sess_name]=$chars;

    $fontfiles=array("MSYH.TTF","MSYHBD.TTF","SIMLI.TTF","SIMSUN.TTC","SIMYOU.TTF");

....

...

有没有加粗这两句话

$_SESSION['verify']这一个值应该为验证码的session.就是验证码的四个数字。来判断是否相等的。不知道为什么，如果设置为空，那验证码就不能用了