The invention discloses an optical layer protection method for ROADM in a multi-node ROADM ring network, comprising the following steps: (1), dividing the protection type of a service wavelength, a wavelength and a working path and a protection path of transmission according to the priority level of system service; (2), configuring a detector, an actuator and a controller according to the protection type; and (3), collecting and analyzing the detection information of the detector by the controller, and controlling the actuator to switch according to the protection type and an analysis result.Based on the same device, the invention utilizes the characteristic of wavelength reconstruction of ROADM equipment, the controller can control the actuator to carry out different operation accordingto the information of the detector, the switching of various protection types is flexibly realized under the precondition that hardware equipment is not replaced, the effect of the fast scheduling ofservice resources by the optical network is achieved, the cost of service fulfillment is saved, the speed of service fulfillment is enhanced, and the utilization of system resources is optimized.