<p>Method, device and system of data synchronization are disclosed, which relate to field of communication technology. The method of data synchronization includes: composing identification with respect to at least two pieces of requested synchronization data into an identification combination; sending a data synchronization instruction, where the data synchronization instruction includes a synchronization request and identification combination for at least two pieces of data; receiving the requested synchronization data of the data synchronization instruction, and updating the data that need to be synchronized according to the received data.</p>
