Abstract: In order to study the influence of pollutants reduction rate on different installation spacing of biological carriers,rope artificial water plants,biological curtains and carbon fiber water plants,which are widely used in domestic water environment project,are selected to conduct a 15-day trial on waste water. The results are as follows:（1） The pollutants reduction rate increases with the decreasing spacing of the rope artificial water plants and carbon fiber water plants,when the rope artificial water plants are at 10 cm spacing treatment and the carbon fiber water plants are at 15 cm spacing treatment,the comprehensive reduction rate of pollutants is the largest,the corresponding average reduction rates of total nitrogen,total phosphorus,ammonium nitrogen,and COD are 0.38,0.32,0.34,0.44 and 0.44,0.35,0.35,0.52,respectively. While biological curtains show an opposite trend,when the biological curtains are at 60 cm spacing treatment,the comprehensive reduction rate of pollutants is the largest,the corresponding average reduction rates of total nitrogen,total phosphorus,ammonium nitrogen,and COD are 0.42,0.35,0.42,0.52.（2） It’s recommended that the arrangement installation spacing of rope artificial water plants and carbon fiber water plants is 10～15 cm and 15～20 cm respectively,the installation spacing of biological curtains should be large rather than small,the recommended installation spacing is about 60 cm.（3） Biological curtains are the most cost-effective,followed by rope artificial water plants,while carbon fiber water plants have the lowest cost-effectiveness. Meanwhile,the larger the installation spacing,the better the cost performance within the test range.