With the development of emerging technologies such as Internet, mobile Internet, cloud computing, big data and the like, the use mode of various service application systems starts to change. More andmore applications for a mobile terminal are provided, but data use of a service system can be influenced due to instability of a mobile network, so that a data synchronization problem of an off-line application solves the technical barrier of the current mobile Internet software development. A universal off-line application technology is completed based on a server, and data synchronization situation judgment is carried out by the server, the technology has larger requirements for configuration of the server, network bandwidth and other hardware devices, and the use defects exist. The invention provides an off-line system data synchronization method, a time stamp is marked through interaction information between the server and a client at the client, and the time stamp serves as a condition for judging whether synchronization is needed. When the client is in an off-line state, the information is stored in a local database, a time stamp difference is judged when the network is restored,data synchronization is carried out, and the off-line system application is realized.