Abstract: Three aquatic floating plants,Lemma polyrhiza L.,Pistia stratiotes,and Eichhornia crassipes,to treat the water eutophication were studied. The results indicate that these three plants can reduce the N and P,increase the dissovled oxygen,and restrain the growth of algae efficiently in eutrophication waters;however,the sequence of treating efficiency is Pistia stratiotes＞Eichhornia crassipes＞Lemma polyrhiza L.Pistia stratiotes and Eichhornia crassipes have strong abilities to suit the various environment,and the growth of Pistia stratiotes is easily to control.Therefore,Pistia stratiotes is recommended as a preferable aquatic floating plant to treat eutrophication waters.