The invention discloses an enterprise mobile office system and method based on groups. The enterprise mobile office system comprises a subscriber data center, a mutual communication center, a cache center, an identification center and at least one exchange center; each subscriber is linked to the subscriber data center through the identification center, the subscriber data center is linked to the cache center and each exchange center, and each exchange center is linked to the cache center and is communicated with the mutual communication center. The enterprise mobile office method comprises daily work report, task allocation, task cooperation, report implementation, application applying, announcement issuing, financial management, enterprise culture propaganda and staff communication and point-to- point message delivery. The enterprise mobile office system based on groups has functions such as task allocation, daily work report, task cooperation, application management, announcement issuing, point-to-point communication and subscriber-defined group communication, and the flat management among the enterprise sectors is achieved.