Abstract: Focused on a malodorous river in Shanghai, a set of staged floating treatment wetlands (SFTWs), by simulating ecological niche distribution of hydrophyte in nature water with three kinds of hydrophyte, Hydrocotyle vulgaris, Nymphaea tetragona, Myriophyllum verticillatum, was designed. The results showed that the average removal rate of ammonian was 71.9%, with 36.1%, 22.3% and 13.5% of ammonia nitrogen being removed by the unit of emergent plants (Hydrocotyle vulgaris) , floating plants (Nymphaea tetragona) and submerged plants (Myriophyllum verticillatum) respectively. Nitrite nitrogen was accumulated in the staged ecological floating wetlands. The average concentration of nitrite in the floating plants unit and submerged unit rose to 1.4 mg/L and 1.5 mg/L from 1.3 mg/L respectively. At the same time, the nitrate nitrogen concentration in the unit of emergent plants and the unit of submerged plants unit is lower than that in the unit of floating plants, also accumulated in the system. The average removal rate of total inorganic nitrogen, mainly by the unit of emergent plants (up to 24.8%), was 45.0%.