Ad hoc network routing protocols can be designed to give better energy conservation performance. We summarize the problems of power control in wireless ad hoc networks. The main discussion is to propose an energy-efficient reactive routing protocol. For such a routing protocol some related topics are considered, such as MAC layer requirement, transmitter power imbalance, route establishment, and route stability. Our protocol can be applied to some existing reactive routing protocols such as AODV or DSR to give significant efficient energy performance. A simulation model is used to test the performance and the results show that our protocol gives significant energy saving and improves link stability as well.