The embodiment of the invention discloses a method for data synchronization, which comprises the following steps: data which is required to be synchronized is determined by comparing data fingerprints in a database on both sides requiring data synchronization; then, data synchronization is carried out on the data requiring to be synchronized. The embodiment of the invention also discloses a data synchronizing system and two data synchronization devices. The technical proposal of the embodiment of the invention realizes data synchronization by the data fingerprints, thereby avoiding transmitting of large amount of data between both sides of data synchronization.