In order to reduce the pollution of cage culture to waters, Pistia stratiotes were respectively planted in an experimental cage and a comparison cage, which were compared and analyzed. The results showed that Pistia stratiotes and their attachments in the experimental cage had significant removal efficiency of nitrogen and phosphorus in the waters. 201.26 g nitrogen and 71.53 g phosphorus were removed by Pistia stratiotes; and 5.91g nitrogen and 3.01g phosphorus were removed by Pistia stratiotes’ attachments in the 30-day experiment. The amount of nitrogen and phosphorus removed by Pistia stratiotes’ attachments were 2.94% and 4.21% of those removed byPistia stratiotes. The recovery rates of nitrogen were significantly different(P < 0.05) in the experimental cage and the comparison cage, which were (41.27±1.28)% and (37.15±1.26)% respectively; and the recovery rates of phosphorus were significantly different(P < 0.05) in the experimental cage and the comparison cage, which were (31.26±1.27)% and (27.87±1.13)% respectively. The utilization rates of nitrogen were significantly different(P < 0.05) in the experimental cage and the comparison cage, which were (26.32±2.32)% and (17.21±0.51)%, respectively; and the utilization rates of phosphorus were significantly different(P < 0.05) in the experimental cage and the comparison cage, which were (23.15±1.75)% and (14.63±0.43)% respectively. The result showed that Pistia stratiotes and their attachments can reduce the pollution of cage culture to waters through absorbing the nitrogen and phosphorus in the waters.