This paper proposes a new synchronization algorithm which introduces the concept of event correlation into Emewarp algorithm. Under this synchronization mechanism, state rollback is executed only when there exists an event whose timestamp is within the rollback time and the event is related with others that should be executed after it but has been done before. The simulation results show that the improved algorithm can reduce the rollback number effectively and decrease playout delay, so that MMOG's interactivity and playability are uplijled.