Abstract: Wetlands which are the transition areas between riparian land and river water in watershed ecosystem play important roles in the pollution control, biodiversity conservation and erosion and sediment reduction. In order to reveal the pollutants reduction characteristics of wetlands in the upper, middle and lower reaches of Liaohe River Basin, and to quantitatively compare the differences of the purification effects of the wetlands, the water quality and quantity at the junction of East and West Liaohe River, Qixing Wetland and Liaohe River Estuary Wetland were monitored on the spot, the status of water pollution was analyzed by Nemerow pollution index, and the pollutant removal effect of wetlands was empirical evaluated. The results showed that Nemerow pollution index at the entrance of tributary rivers were higher than that in central wetlands and at wetland water outlets. The water pollution status would be gradually alleviated owing to purification effects of wetlands along with the distance away from the tributary estuary. The reduction effects in the above three wetlands on the pollutants were different mainly due to the structural, complex and regional characteristics of water pollution in the tributary rivers.