In order to resolve the problem of file sharing of multi-user collaboration in the Department Office of NCTUCS, we design and develop CSDrive - a private cloud storage services. In addition to offering web interface and communications protocols for accessing files on private cloud, CSDrive also provides file operation history, file versioning, file recycle bin and file publishing, etc. Compare to other private cloud storage service solutions, file versioning feature of CSDrive can more completely record and generate content differences between different users on different work phase. Besides, file publishing feature of CSDrive is based on the requirements of Department Office of NCTUCS, which is more suitable for external publishing of official documents.