In the electrical power system, there is a wide range of communication services and service needs, and the realization of differentiated services of different types is quite necessary. Thus, based on the combination of characters and requirements of electric power communication business, this paper makes an argument for a routing and wavelength assignment algorithm based on prediction and layered graph model (PLGMRWA). Through the wavelength number prediction mechanism, it realizes the distribution of wavelength resource according to the needs, and uses the layered graph model to wholly solve the problems of route and wavelength assignment in comprehensive considerations of hops and the usage of wavelength. The simulation results indicate that, algorithm PLGMRWA has advantages of blocking capacity and wavelength resource utilization over algorithms GWAS (Grouped wavelength assignment strategy) and DPWA (Dynamic and priority-based wavelength assignment algorithm) for all levels of business in electrical power communication network.