In order to distribute net resource reasonably and gather better performed information to fulfill tasks and improve the locating accuracy of events, a wireless sensor network locating algorithm, called improved particle swarm optimizationimproved received signal strength indicator(IPSO-IRSSI), based on relative received signal strength(RSSI) and the split-step particle swarm optimization algorithm is proposed. Based on the analysis of RSSI radio propagation loss model, combined with the idea of survival of the fittest selection and adaptive weight approach of the optimal objective function the proposed algorithm, promotes a mechanism of filtration of anchor nodes and a particle swarm optimization step algorithm. Simulation experiments dates show that the algorithm obtains a better locating accuracy and is superior to the distance related traditional locating algorithm.