项目根目录下的Web.config
<system.web>
<customErrors mode="On" defaultRedirect="~/Error/Index">
<error statusCode="500" redirect="/Error/page_01" />
<error statusCode="404" redirect="/Error/page_02" />
</customErrors>
</system.web>
原文：http://www.cnblogs.com/hcfan/p/4892705.html