An embodiment of the invention provides a project file based internal and external cooperative office management system. The system includes an internal office management system and an external officemanagement system in mutual communication, wherein a second database of the internal office management system is isolated from a first database of the external office management system .The externaloffice management system includes a catalog creating module, a file importing module, a format copy creating module, a document creating module, a document receiving module and a document checking module. The internal office management system includes a file creating module, a file sign-in module, a file service version modifying module, a file linking module and a file subscription module. According to the invention, independent management of files of different persons can be realized, so that file management safety is ensured. Also, cooperative office of internal and external staff of a system can be realized.