public void sendEmail(string email)
    {
        string smtp = "smtp.163.com";
        string mailForm = 发送人帐号;
        string mailPwd = 发送人密码;
        string mailTo = email;//接收人邮箱帐号
        string mailTitle = "邮件标题";           
        string mailContent = 邮件内容;    
        SmtpClient client = new SmtpClient(smtp);
        client.UseDefaultCredentials = false;
        client.Credentials = new NetworkCredential(mailForm, mailPwd);
        client.DeliveryMethod = SmtpDeliveryMethod.Network;
        MailMessage message = new MailMessage(mailForm, mailTo, mailTitle, mailContent);
        message.BodyEncoding = Encoding.Default;
        message.IsBodyHtml = true;
        client.Send(message);
    }

试试这段代码。