As a key data in electric power communication network, link importance is very important for network optimization, security and maintenance of electric power communication network. In this paper, a power communication network model with master and standby routing services based on SDN architecture is constructed, and a link importance evaluation algorithm of power communication network under SDN architecture is proposed. A method of dividing links into three network layers is proposed to evaluate the importance of links quantitatively. Compared with the traditional power communication network link importance analysis method, the simulation results show that the algorithm has a significant effect on the evaluation of link importance.