Disclosed is a client-based network data synchronization method. The method comprises: a serving end receiving user operation data recorded by a client; when receiving a data synchronization request for synchronizing server data from the client, acquiring data to be synchronized from the received user operation data recorded by the client according to a priority level of the user operation data; and taking the acquired data to be synchronized as synchronization data and sending same to the client. Also disclosed are a client-based network data synchronization apparatus and system. The implementation of the embodiments of the present invention can improve the data synchronization efficiency.