Purification of small enclosed surface water was made by carbon fiber ecological grass. The results show that the ecological grass disperses in the presence of water, and its large specific surface area is beneficial to microbial attachment and growth. The film-forming process takes less time, and the biofilm form is stable. Carbon fibre ecological grass can improve and maintain water quality to a certain extent with COD removal rate at 71%. But the removal effect of TN and TP is not obvious. On the whole, the water quality can meet the IV standard of surface water environment continuously.