Abstract: Wireless Sensor Networks (WSNs) have inherent and unique characteristics rather than traditional networks. They have many different constraints, such as computational power, storage capacity, energy supply and etc; of course the most important issue is their energy constraint. Energy aware routing protocol is very important in WSN, but routing protocol which only considers energy has not efficient performance. Cluster-head election problem is one of the basic Qos requirements of WSNs, yet this problem has not been sufficiently explored in the context of cluster-based sensor networks.