Abstract: Compared the capability of water purification among various hydroponic plants（Nymphaea L., Oenanthe javanica （Blume）DC, Canna indica L. and Ipomoea aquatica Forsk）in two different aquaculture water（TN=23.5 mg/L, TP=1 mg/L;TN=40.5 mg/L, TP=2 mg/L）, and the results showed that 4 hydroponic plants had significant ability of removal nitrogen and phosphorus. After 168 h, total nitrogen（TN）removal rate is 56%~83%, and total phosphorus（TP）removal rate is 80%~81% in middle eutrophic aquaculture water. Total nitrogen（TN）removal rate is 60%~83%, and total phosphorus（TP） removal rate in high eutrophic aquaculture water is 80%~85%. All four different hydroponic plants removal rate of TN and TP rose up in daytime but dropped at night. It also showed that, Nymphaea L. and Canna indica L. had better removal rate of removal phosphorus and nitrogen than Oenanthe javanica（Blume）DC and Ipomoea aquatica Forsk.

Key words: eutrophication water, phosphorus removal, nitrogen removal, the removal rate, hydroponic plant