This paper reported the removal efficiency of nitrogen in a downflow upflow constructed wetland purifying system with intermittent loading,and described the changes of temperature, dissolved oxygen and pH. The result indicated that the system was in unstable condition at the beginning of operation, and the removal efficiency was not remarkable. The removal efficiency of KN, NH\++\-4 N and NO\+-\-2 N become significant as the system becomes stable, and the average removal rates are 50%, 66% and 71% respe...