I want a p2p mobile file sharing application .
I want to know which technology can be used to make this kind of application.

There are several portable applications that utilize the gnutella and bittorrent protocols. You could probably code one using C#, C++, or JAVA in a matter of days if you are any good at any.

µTorrent Portable

Frostwire Portable (Still Buggy)

Search around there are quite a few. Good Luck