In order to solve the network resource bottleneck problem of the electric power communication system in the process of the development of the power grid，the application of P-cycle protection in the electric power communication network is explored in light of the status quo of the network.The P-cycle straddle link protection interface on the advanced add/drop multiplexer（ADM）is introduced to provide highly efficient cycle protection.A mathematical model for network resource allocation is developed，and a heuristic algorithm is provided to support the integer linear programming（ILP）model.The candidate P-cycle set is calculated with the straddle link algorithm and the protection bandwidth is dynamically allocated according to the newly started service factor and the number of stations directly connected to a 500 kV substation to reduce the probability of bottleneck station.On this basis of P-cycle enumeration algorithm，a heuristic resource iterative algorithm is proposed to improve the resource utilization with regulated routing information.Examples of the 500 kV fiber optic network in the eastern region of Guangdong power grid is presented as an example to illustrate the efficiency of the proposed approach.Resource redundancy and transaction blocking are analyzed and the prospects for future application are treated.