The invention discloses a server application method for cloud disc data synchronization, and the method comprises the following steps that a cloud server numbers a terminal which logs in a cloud discfor the first time according to the ID of the terminal, and synchronizes the cloud disc data to the terminal when the terminal which logs in the cloud disc for the first time; the cloud server storesoffline modification and the terminal ID uploaded by the terminal after network connection, and transmits the modified content data to the cloud disc for storage; the cloud server judges whether the ID of a terminal which logs in the cloud disc for more times is the same as the ID of the terminal which submits the modified contents or not: synchronizing the cloud disc data to the terminal if the ID of the terminal which logs in the cloud disc for more times is not the same as the ID of the terminal which submits the modified contents, or else carrying out the no operation. According to the invention, the ID of the terminal is obtained during the logging-in of the terminal so as to judge whether the terminal is the terminal which modifies the cloud disc data locally last time, thereby solving a problem that the piece-by-piece judgment or direct synchronization causes the bigger data size in the prior art.