Abstract: Water hyacinth（ Eichhornia crassipes） is good at water purification，but so far it has not been widely used in water quality improvement and aquaculture ecological restoration. To investigate the effects of water hyacinth on water quality，sediment deposition and plankton，water hyacinth was planted（ 10 plants per square meter） in largemouth bass（ Micropterus salmoides） aquaculture pond for 8 d. The results showed that the water hyacinth had no obvious effect on the Power of hydrogen（ pH） of the water，the maximum removal rate of ammonia nitrogen（ NH4 +-N） in the water was 60.9%，and the total nitrogen（ TN） removal rate was 59%. After treatment of water hyacinth，the maximum removal rate of sediment organics was 65.6%，and the maximum removal rate of sediment phosphorus was 46.9%. The effect of water hyacinth on the total amount of plankton was small，while the biomass of Chlorophyta and Cyanobacteria was significantly reduced，and it suggested that water hyacinth could manipulate the structure of phytoplankton population.