Abstract: The mechanism for green unicast routing protection is designed with the constraint of quality of service (QoS), energy consumption and the survivability of single link or node failure considered. The path is calculated under the constraint of QoS based on K-shortest path algorithm. The resource allocation is done on multi-layer auxiliary graph considering the minimum times of wavelength conversion. Three protection levels are provided according to the service demands. The mechanism is implemented over EON (Europe optical network) topology by simulation. Performance evaluation has been done on the blocking probability, the protecting/working resource ratio and the load balance degree by comparing with certain existent mechanism. It has been shown that the proposed mechanism is both feasible and effective.