Abstract: Effects of ecological floating rafts on water quality of intensive aquaculture ponds were studied using ammonium nitrogen (NH₄ -N), nitrite nitrogen (NO₂^--N), nitrate nitrogen (NO₃^--N), orthophosphate phosphorus(PO₄^3--P), total nitrogen (TN), total phosphorus (TP) and COD_Mn as main water quality indexes, and its mechanism of purifying the water was explored in an experiment. The results showed that the four treatments followed a decreasing order of control group＞treatment 5%＞treatment 10%＞treatment 20% on the same conditional experiments. And the removal rate of in treatment 20% was higher than the other treatments, as follows 42.82%, 39.47%, 43.8%, 64.1%, 46.57%, 58.75%, 7.4%. The yield of Ipom oea aquatica, harvested six times, reached as high as 14.3-17.6kg/m². In treatments 5%, 10% and 20% 1643.5, 988.2 and 5341.3 g/667 m² of TN and 240.7 g, 437.6 g, 5341.3 g/667 m² of TP were respectively, removed with the harvest of Ipom oea aquatic. The tilapia survival rates in the treatments improved significantly as is compared with that in the control group. So it was obvious that in ponds rearing of tilapias, cultivating Ipom oea aquatica on artificial floating rafts could purify of water quality reduce the pond eutrophication. So that treatment 20% has certain value of application in ponds rearing of tilapias.