A dynamic clustering method of wireless sensor network for target tracking was proposed considering residual energy and received signal energy intensity of nodes.Because the residual energy of the nodes was considered when choosing cluster heads the fail of tracking caused by shortage of node's energy could be avoided.The method can not only make each node play the role of cluster head evenly but also avoid the cluster heads switching too frequently.Therefore the life of network can be prolonged tremendously.The results of simulations show that:to satisfy the energy requirement of cluster head and guarantee that most of the nodes of cluster can sense the target the energy threshold should be as small as possible and the distance threshold should be as big as possible.