Ecological ditches (eco-ditches) are being recognized as a green method for treating wastewater from domestic sewage sources. However, the relationship between the efficiency of nutrient removal from wastewater and N2O emissions is unclear given that a higher nutrient removal efficiency might result in more N2O emissions. Therefore, we constructed an eco-ditch system with three combinations of different plants (local wetland species) to treat rural sewage in the mountainous regions of China and monitored water quality and N2O emissions. Eco-ditches are important sources of atmospheric N2O, with nutrient removal efficiencies of 22-84% and 23-87% for total nitrogen (TN) and total phosphorus (TP), respectively, and emissions of N2O ranging from 16 to 243 mu g m(-2) h(-1). The seasonal variations in pollutant removal efficiency and N2O emissions followed similar patterns-both were considerably greater in summer than in the other seasons, with the lowest values observed in winter. Among the three plant configurations tested, ditch sections containing Acorus calamus L. and Phyllostachys heteroclada Oliv. had the highest nutrient removal efficiency and the lowest N2O emissions, with removal efficiencies of 24% and 32%, respectively, for TN and TP, and a 16% average reduction in N2O emissions, which was positively associated with NO3-N. This study highlights the importance of selecting appropriate combination of plant species for eco-ditches to efficiently remove nutrients from rural domestic sewage and reduce N2O emissions.