In the smart grid, to improve the quality of service and to reduce the risk of network much further is the main research direction. How to choose a highly reliable, stable and low-risk routing is the most critical part of the smart grid. The factors considered by most existing algorithms do not sufficiently consider redundancy, so that optimization is not sufficient. Therefore, based on service path pressure and the special factors of the power communication network, this paper proposes a kind of multi-constrained maximally disjoint routing mechanism and states the superiority of this algorithm via experiment which is simulated on the power communication network of a certain province.