The invention relates to a main and standby server system and a data synchronization method, and belongs to the technical field of computer software. According to the invention, temporary data tablesare added in the main server and the standby server; and the main server historical storage service stores the stored historical data into a local corresponding historical data table, writes the datainto a local temporary data table, monitors the standby server to periodically retrieve the main server temporary data table, and synchronizes the data to the local historical data table to finish thehistorical data synchronization between the main server and the standby server. Through the above process, the method can effectively solve the problems of network abnormality and inconsistent data during main and standby switching, improves the reliability of data storage of the main and standby servers, and guarantees the normal operation of the main and standby servers.