The invention discloses a wide area file system and an implementation method, and relates to the technical field of file systems. The implementation method for the file system is applicable in a wide area. According to the system, an event-driven module receives an operation request, whether a file exists in a local cache is inquired through a cache management module according to the node number of the requested file, if yes, the file is accessed from the cache, if not, the path name, in a server end database, of the file is inquired according to the node number and through a node management module, then the file and the meta-information of the file are obtained according to the information of the operation request and through an event processing module and are sent to the cache management module, and finally, the cache management module stores the file and the meta-information of the file into the local cache. The wide area file system and the implementation method do not rely on a bottom file system, it is only needed that the bottom file system can be shared, the space management function of the cache is provided, and the resource utilization rate of the system is increased.