Abstract: In this paper,it present an Energy Efficient Routing Protocol(EERP).The main idea is to strike a value of cluster radius in every level from the most far level to the nearest one,and make the radius of the clusters near the sink node less than the radius far from the sink node.The node's ability to be cluster head is determined based on the residual energy and their relative distance;inter-cluster using dynamic routing;cluster is rebuilding based on received bit value and the residual energy of cluster head.The results of simulations in OMNET++ show that EERP improves obviously in balancing energy consumption between nodes and prolonging network's life period.