Abstract: Mobile Ad hoc network (MANET) is a multi-hop non-centric self-organizing wireless network, in which there are two important route optimize metrics-- load and energy. It is hard to fully describe the two metrics by using numerical value because of their dynamical varieties during routing process. With the idea of fuzzy sets and fuzzy logic, this paper proposes a fuzzy logic and state aware routing protocol (FLSAR), and presents an integrated route metric combining load and energy, which enables them to be balanced in the whole network. The simulation by NS2 illustrates that the throughput and lifetime of network are effectively improved.