The Songhua River Basin is one of the important distribution areas of the wetland wetlands in China. However,due to the impacts of global climate change and human activities,the wetland area in the basin is decreasing. Based on the RS and GIS techniques,we discussed the concept of the biochemical rate of Paolu wetland, the degradation rate of foie far wetland and the retention rate of Paolu wetland. The results showed that the area of wetland was reduced by nearly 50% from 1950s to 2015. The reduction of the wetlands was mainly for cultivated land,grassland and saline land. The rate of arable land was 63%,and the degradation rate of Paolu wetland was 36.5%. The strong development of cultivated land by mankind was the most important factor result in the reduction of the wetland of the Songhua River,and because human activities blocked the connectivity between the river and the wetland,it caused the water shortage of the wetland,and also caused the reduction of the wetland area.