I had located the problem.
The GameObject Basement(_SetGeometry=>Basement=>Basement) in the demo scene:Basement is the problem.When I delete it or enable it.Everything is ok.When I enable the Basement object.The unity goes no response.
When I switch to android platform,The unity will begin to switch.But in the process of switching Unity has no response,And cpu usage of unity is always about 50% .I create a new unity project and import Adventure Creator 1.52.And do nothing else.