Abstract: In order to study the purification and restoration effects of water hyacinth（Eichhornia crassipes） on different eutrophication levels of water, water culture tests were conducted under five different concentration gradients from Grade III to worse than Grade V according to the China Surface Water Environmental Quality Standards to investigate the purification effect of Eichhornia crassipes on COD_cr, TN and TP in wastewater with different initial concentration. When the initial concentration of wastewater were COD_cr 25.720~136.040 mg/L, TN 1.263~32.011 mg/L and TP 0.942~4.111 mg/L, respectively, the purification effects of Eichhornia crassipes on COD_cr, TN and TP were well, the removal rate tends increased with increasing of initial concentration, the maximum removal rates could reach 80%, 97% and 98%, respectively. The results showed that the Eichhornia crassipes had satisfactory repair effect to different eutrophic water, especially suitable for purifying and repairing water worse than Grade V.

Key words: water hyacinth（Eichhornia crassipes）, eutrophic water, purification effect