The present invention relates to a MAC address synchronization method and apparatus for an OLT device. The method mainly comprises: a stacking system completes selecting master and standby control boards, and advertises information of the master control board to all stacking devices in the stacking system in a multicast manner; the stacking devices register and subscribe to MAC address entry events to the master control board; forwarding planes of the stacking devices report, to a control pane of the master control board, MAC address entry events to be processed in batches; the control plane of the master control board performs local MAC address entry processing on said MAC address entry events according to the time sequence, and sends said MAC address entry events in a multicast manner to all the stacking devices that subscribe to the corresponding events; upon receipt of said MAC address entry events, the stacking devices perform local MAC address entry processing. The present invention can ensure the synchronization timing of a MAC address table, solves the problem in the prior art of the abnormal time sequence, can ensure the normal operation of MAC aging, and can also flexibly extend an uplink port of the system to achieve the purpose of newly adding the stacking device.