I use Nant to run the test with Nunit.
Is it possible to set the time in the Nant .build file,
and let the test run in the time as I set.
And if it can be execute ,how can I write the build file?
It sounds like you're talking about setting up a continuous integration environment.
I highly recommend you look into Jenkins as it's extremely easy to get up and running, and will do exactly what you want.