A data synchronizing method between a server and a client is provided. The server and the client manage database changed after a previous synchronization of data shared by them. The database includes a sync anchor field for each data item. When a sync session is initiated upon request of the client, a last anchor is detected from the database stored in the client and a last anchor from the database stored in the server. The last anchor of the client is compared with the last anchor of the server. A client change log and a server change log are generated according to a comparison result based on a database change that occurred after the last anchor of client or server when the last anchor of the client is identical to the last anchor of the server. The databases are updated according to the client change log and the server change log.