A survivability strategy based on CRDD（conditional risk disjunction degree） in multi-domain optical networks was provided in order to overcome the defect of the scalability constrained and provide differentiated service. The con- cept of CRDD was provided in this strategy

then the intra-domain virtual links reflection was achieved and the end-to-end work route and backup route to differentiate service reliability were computed with CRDD. The results show that the supported survivability strategy not only can differentiate the service reliability

reduce the blocking probability of service

but also can improve reliability for service requirement by 6.5% on average.