We are using one of the project from Github. We need to check-in code of this project in our TFS.
We need to automate this process. Else everyday we need to download
If you are using a TFVC repository in TFS then you'll probably want to build some scripts and a process around Git-TF to help automate some of this work.
If you are using a Git repository in TFS then you can create set up two remotes in a local Git repository, i.e
git remote add upstream https://github.com/foo/bar.git
git remote add origin https://tfsserver/DefaultCollection/_git/bar
And then simply do a git pull upstream master followed by a git push origin master assuming that master is the branch that you want to keep in sync.
With either version control system, you probably want to keep a branch in version control in your TFS repository to match what is in your upstream GitHub project so that you can easily see change coming in the one place and then handle your merges inside your local repository.