|To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07∼1.47, 0.60∼2.65, 0.50∼4.60, 1.38∼6.26 and 0.08∼0.32 mg L-1, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was 368.7 mg plant-1 in the 2nd treatment stage by Nymphoides peltata, 1314.6 mg plant-1 in the 3rd treatment stage by Iris pseudacorus, 1160.4 mg plant-1 in the 4th treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was 121.7 mg plant-1 by Nymphoides peltata in the 2nd treatment stage, 268.7 mg plant-1 by Iris pseudacorus in the 3rd treatment stage and 212.0 mg plant-1 by Nymphaea tetragona GEORGI in the 4th treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117～140:1～4:1, 86～126:5～6:1, 68～101:2～6:1 and 47～138:2～4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.