Removal efficiency of nitrogen, phosphorus and N2O emission from domestic sewage in floating-bed system with Lolium mutliflorum, Oenanthe javanica and Vetiveria Zizanioides were investigated in greenhouse. Results showed that all three plants had good removal efficiencies of total nitrogen (TN), ammonia-nitrogen (NH₄⁺-N) and total phosphorus (TP) from domestic sewage in the floating-bed system. In comparison with the none-plant system, the three plants increased averagely the TN removal rate by 26.2%，22.9% and 4.1%, the NH₄⁺-N removal rate by 31.4%，14.5% and 3.0%,and the TP removal rate by 33.1%，54.2% and 15.5%, respectively. With retention time prolonged, the concentrations of TN, NH₄⁺-N and TP of domestic sewage were obviously reduced in all floating-bed systems, however the NO₃^--N concentrations were gradually accumulated due to the stronger nitrification than denitrification. The plants in floating-bed system increased significantly the N₂O flux, which was 174.44 μg/(m²•h)，82.19 μg/(m²•h)，112.49 μg/(m²•h) and 44.81 μg/(m²•h), respectively, for the Lolium mutliflorum, Oenanthe javanica, Vetiveria Zizanioides and none-plant floating-bed systems. The N₂O flux from all floating-bed systems increased during the day but decreased during night followed the change pattern of temperature, suggesting that the N₂O production and emission was affected by the temperature.