The invention discloses a multilayer protection switching method and device in an optical network. The multilayer protection switching method comprises the following steps: whether a client layer and a service layer fail is judged; when detecting that only the client layer fails, a client layer APS process starts and executes bridging after the operation is completed; when detecting that the service layer or the client layer and the service layer fail(s), the APS processes of the client layer and the service layer start simultaneously, and after the operation is completed, the APS process of the client layer is in a hold mode, and does not execute the bridging operation; the state of a protection switching state indicator is detected, and if the protection switching state indicator shows that the bridging of the service layer is successful, the APS process of the client layer is zeroed; and if the bridging of the service layer fails, the client layer executes bridging immediately. The method and device have the advantages that by the protection switching state indicator of the service layer, the protection switching actions of the client layer and the service layer are coordinated, and the parallel working of the protection switching processes of the client layer and the service layer is realized, so that the protection switching time is shortened.