With the progress of CNC(Computer Numerical Control) technology, CNC system has developed from a stand-alone system to a distributed system. The capacity of the machine storage can't meet the needs of complex numerical control program. Applying NFS(Network File System) service to the distributed CNC system can solve the problem of limited storage space, and is convenient for users to manage the shared files. This paper introduces the key technology of NFS and changes the resource allocation strategy from using IP address to using user information.