Abstract: This paper presents a cluster head selection algorithm based on fuzzy logic. Firstly, it has some important input variables such as residual energy, density and distance to the base station. Secondly, it makes some fuzzy rules. Then it Calculates a probability of cluster head through the fuzzy inference system. Finally, it improves the threshold value by the probability. Simulation results show that the algorithm can make the network more balanced energy consumption, effectively prolong the network life cycle compared with the LEACH protocol.