In order to enhance coverage effect of large-scale wireless sensor networks（ WSNs） for water environment monitoring of the Three Gorges reservoir and prolong survival time of large-scale WSNs

using the chaos artificial fish swarm algorithm（ AFSA）. First

using maximize network coverage as optimization objectives and establish WSNs coverage model

then apply the chaotic system which has characteristics of ergodicity to AFSA

the algorithm can effectively avoid to be located near the local extremum for a long time. Simulation results show that the improved AFSA improves network coverage rate

effectively reduces cost of the network.