Data synchronization method, apparatus, and system

The present invention provides a data synchronization method, comprising the following steps: acquiring to-be-synchronized first data; determining, based on a data serial number and data characteristic information, whether data information that comprises at least one of the data serial number and the data characteristic information and is different from any data information in the other one of the first data and second data exists in the first data and the second data; and when it is determined that different data information exists in the first data and the second data, sending the determined different data information to a server, so as to synchronously update corresponding data stored in the server, to obtain third data after current synchronization processing. This method solves a problem that a synchronization client can accurately find to-be-synchronized data in the case of having no data operation log, which has the advantages of convenience, instantaneity, high efficiency, and applicability. Further disclosed are a data synchronization apparatus and a data synchronization system.