In this paper, we propose a new routing algorithm which can increase the network lifetime. We assume that each node can estimate its residual energy and then a new clustering method will be proposed for increase of network lifetime. This assumption is similar to many other proposed routing algorithms for WSN and is a possible assumption. In the new method, the predefined number of nodes which have the maximum residual energy are selected as cluster heads (CHs) first and then the members of each clusters are determined based on the distances between the node and the cluster head and also between the cluster head and BS. In fact, the selection of each cluster member is done based on the maximization of the residual energy for nodes which build a path to BS unlike the traditional methods that build a path with minimum length to the BS. All cluster heads use a multi-hop chain structure for transmission of data packets from themselves to BS. We compare our method with ERA routing algorithm in terms of network life-time by simulation.