This research used the constructed wetland of Jin-su lake at the Pingtong University of Science and Technology as a experimental site. Because the constructed wetland accepting the aquaculture waste water coming from the upper stream, through the function of absorbing, sedimentation, natural purifying and plant purifying etc., the nutrients and pollutant of this waste water can already be got rid of effectively. Thus, the effluent water quality gradually becomes more and better. Measure result show although waste water quality improved by the purification function of the constructed wetland, but the pollutantjust changing it type attitude and still stored in the wetland. Because its total amount has not been reduced, in order to move and get rid of the pollutant, must cut and get rid of plant growing and bottom mud of the wetland regularly.