Energy Internet (EI) is the trend of smart grids evolution. Since there are large number of services with different performance requirements in the EI. To ensure its smooth operation, it is necessary to design reliable routing algorithms. However, the existing routing strategies in the IP layer place more emphasis on algorithm robustness but neglect resource use in the optical layer as well as characteristic of EI network structure. Actually, resources status of the optical layer affects the availability of the routing algorithm. In view of this, we propose a cross-layer reliable service routing approach, which comprehensively service characteristics in the application layer, link satisfaction and spectrum resources status in the optical layer. The final objective is to satisfy service QoS requirements and ensure services evenly distributed in the network. To reduce the computational complexity, a heuristic algorithm is designed. Extensive experiments are carried out, and the simulation results reflect that the proposed algorithm is superior to the existing algorithms according to the service blocking ratio(SBR) and service distribution fairness index.