Abstract: An indoor hydroponic experiment was conducted to study the removal effects of nitrogen and phosphorus in eutrophic water of four wetland plants in Mocanxi river entering Erhai Lake， i.e. Myriophyllum verticillatum L.， Eichhornia crassipes （Mart.） Solms， Thalia dealbata， Scirpus validusVahl，and plant communities they construct. The international standard detection method and weighing method were used to measure and analyze the three indexes of total nitrogen， ammonia nitrogen and total phosphorus in water and the fresh weight of plants regularly， and the aquatic plants with strong purification ability of nitrogen and phosphorus in water were screened out.The results showed that the four plants and their communities had a good purification effect on nitrogen and phosphorus in eutrophic water.Among them， the growth of Eichhornia crassipes （Mart.） Solms is good and its purification effect is the best.

Key words: eutrophic water, aquatic plants, water purification effect, plant restoration