Aiming at the problem of identifying key nodes in a network,an entropy based network node importance evaluation method,namely EnRank algorithm,is proposed.By defining the attraction rate AR and the transmission rate TR of each node in the directed weighted network,the degree,attraction rate and transmission rate of the node are comprehensively calculated by entropy method,and the comprehensive evaluation index of node importance is obtained.The algorithm considers both the importance of nodes themselves and the relative importance of neighboring nodes.The reliability of the method is verified by simulation experiments on ARPA network and social network.