To evaluate the aquatic ecological characteristics in Sinpyongcheon constructed wetlands for treating nonpoint source pollution, the removal rates of nutrients in water, the total amounts of T-N and T-P uptakes by water plants, and chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD, COD, SS, 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<sup>-1</sup> , respectively. The removal rates of BOD, COD, SS, T-N, and T-P were 14%, 6%, 18%, 24%, and 10%, respectively. The maximum amount of T-N uptake by water plants in August was 813 mg plant<sup>-1</sup> for Phragmites communis TRIV in 2<sup>nd</sup> bed, 1,172 mg plant<sup>-1</sup> for Typha orientalis PRESL in 3rd bed, respectively. The maximum amount of T-P uptake by water plants in August was 247 mg plant<sup>-1</sup> for Phragmites communis TRIV in 2<sup>nd</sup> bed, 359 mg plant<sup>-1</sup> for Typha orientalis PRESL in 3<sup>rd</sup> bed, respectively. Organic matter, T-N, and T-P contents in sediments were high in the order of 1<sup>st</sup> bed > 2<sup>nd</sup> bed > 3<sup>rd</sup> bed. Microbial biomass C/N/P ratios in sediments in 1<sup>st</sup>, 2<sup>nd</sup>, and 3<sup>rd</sup> were 78~110/3~6/1, 73~204/1~6/1, and 106~169/1~6/1, respectively.