Sewage treatment plant effluent water as an landscape water of urban park, has become the practice in northern China through all the city of water shortage. Since nitrogen and phosphorus content of the sewage treatment plant effluent water is relatively high, landscape water eutrophication easily. In this study, the use of carbon fiber artificial plants as ecological group to form biofilms, to study the effect of nitrogen and phosphorus removal process of landscape water. There were 5 kinds of plant densities in the experiment these are 2/m2, 4/m2, 10 /m2, 16/m2, 20/m2. By SPSS, the results showed that the effect of different density of artificial water plants on nitrogen and phosphorus removal was different, the 4/m2, 10/m2, 20/m2 of total nitrogen, ammonia nitrogen, dissolved phosphate had significant removal effect, and the total phosphorus removal was not obvious. Chlorophyll a concentration was positively correlated with the nitrogen and phosphorus removal rate, which indicated that the dominant species of algae in the flowing water had an important influence on the rapid formation of microbial membrane and the place of pollutants.