A data synchronization method for more than three networked devices including at least one client and one server for efficiently synchronizing data among multiple devices supporting a Synchronization Markup Language (SyncML) protocol is provided. The data synchronization method includes determining whether a data item indicated by synchronization information contained in a synchronization request message exists in a change log table of the server, when a server receives the synchronization request message sent by a first client, and updating the change log table by adding the data item indicated by the synchronization information and transmitting a synchronization request message containing a data identifier and the change log of the data item to a second client, if a data item indicated by the synchronization information does not exist, otherwise, ending data synchronization by transmitting a synchronization response message containing status information to the first client.