After getting the System.Reflection.ReflectionTypeLoadException when I am developing with Entity Framework for few weeks, I google a lot and found out a helpful related blog and now I solved my problems.
After following what he mentioned and showed out the real informations from the exception, I figure out that there is a internal developed dll in my project's bin directory, but I never reference it into my project. And this dll is running with another dll from a vendor. The problem never comes up for 2 weeks since I remove that internal developed dll from bin directory. I never expected or think about a "non-reference" existing dll will cause out the problem. Anyway, I hope the rest of the developers who are facing the problem, please read the follow blog, try to implement the code in Global.axas. And I hope the detail information could help you find out what is really going wrong in behind. Cheers~~~
[From Ken Cox] Fed Up With System.Data.Metadata.Edm.ObjectItemAssemblyLoader