<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<security>
<requestFiltering allowDoubleEscaping="True"/>
</security>
</system.webServer>
</configuration>
在WEB.CONFIG配置这样就可以解决
原文：http://www.cnblogs.com/flyfish2012/p/5567995.html