Abstract: Low nitrogen and phosphorus removal capacity had been revealed when integrated vertical flow constructed wetland were on trial to treat urban sewage． In this study，compound bacterium agent and acorus calamus were applied for biological enhancement for an integrated vertical flow constructed wetland． Comparisons had been made on the system's treatment effects under different conditions such as non-enhancing，compound bacterium agent enhancing，and cogradient enhancing of acorus calamus and bacterium agent，and the results showed that after the cogradient enhancement，the system's purifying capacity had been enhanced greatly． The COD and TP of effluent could reach Rank A in the first class discharge standard of China and the effluent's NH+ 4 －N could reach Rank A in second class discharge standard．