An improved algorithm in WSN hierarchical routing protocols was put forward, which considered the residual energy of cluster head selection and multi-hop data transmission from cluster heads to the sink node, to solve the problems of some cluster heads' premature depletion, which affect the whole life of the network, caused by part of the cluster heads over long distances with single hop data transmission to the sink node. Analyses and the simulations were conducted on the first node's death round number and the energy image.The results show that the improved algorithm can balance the network load better and extend the whole network life, compared with the traditional algorithms.