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 stratiotesEichhornia crassipesLemma 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.