Thanks to Don Branson,I solve my problem.I think next time i should use this code when i build my repo on server:
root@localhost:~#mkdir foldername
root@localhost:~#cd foldername
root@localhost:~#git init --bare
root@localhost:~#cd ../
root@localhost:~#chown -R usergroup:username foldername
And on client,i user this
$ git remote add origin git@servername:/var/git/foldername
$ git push origin master