Hi I have ubuntu studio and install Kdenlive but the program did not recognize the camera jvc gr-d250 minidv firewire please help

Using the search I have found this for you...
http://www.kdenlive.org/user-manual/troubleshooting-and-common-problems/troubleshooting-firewire-capture

The referenced post is quite old, but may still be up to date, especially the part about testing the connection with dvgrab from command line.