A method for optical network switching protection, wherein an active optical central office end apparatus and a standby optical central office end apparatus are connected to an optical splitter through a backbone optical fibre, and each optical terminal apparatus is connected to the optical splitter through a branch optical fibre, the method comprising: selecting (201; 404), by the standby optical central office end apparatus, one optical terminal apparatus as a ranging optical terminal apparatus after a service is switched from the active optical central office end apparatus to the standby optical central office end apparatus; obtaining (202; 409), by the standby optical central office end apparatus, a delay difference between a delay from the ranging optical terminal apparatus to the standby optical central office end apparatus and a delay from the ranging optical terminal apparatus to the active optical central office end apparatus; synchronizing (203; 410; 411), by the standby optical central office end apparatus, a time at which data sent by all the optical terminal apparatuses reaches the standby optical central office end apparatus according to the delay difference; wherein the synchronizing the time at which the data sent by all the optical terminal apparatuses reaches the standby optical central office end apparatus according to the delay difference comprises: delivering, by the standby optical central office end apparatus, the delay difference to all optical terminal apparatuses in a multicast or broadcast manner, so that each optical terminal apparatus calculates an Equalization delay, EqD, between the optical terminal apparatus and the standby optical central office end apparatus according to the delay difference respectively, and sets the calculated EqD. selecting (201; 404), by the standby optical central office end apparatus, one optical terminal apparatus as a ranging optical terminal apparatus after a service is switched from the active optical central office end apparatus to the standby optical central office end apparatus; obtaining (202; 409), by the standby optical central office end apparatus, a delay difference between a delay from the ranging optical terminal apparatus to the standby optical central office end apparatus and a delay from the ranging optical terminal apparatus to the active optical central office end apparatus; synchronizing (203; 410; 411), by the standby optical central office end apparatus, a time at which data sent by all the optical terminal apparatuses reaches the standby optical central office end apparatus according to the delay difference; wherein the synchronizing the time at which the data sent by all the optical terminal apparatuses reaches the standby optical central office end apparatus according to the delay difference comprises: delivering, by the standby optical central office end apparatus, the delay difference to all optical terminal apparatuses in a multicast or broadcast manner, so that each optical terminal apparatus calculates an Equalization delay, EqD, between the optical terminal apparatus and the standby optical central office end apparatus according to the delay difference respectively, and sets the calculated EqD.