Abstract: Based on the water quality and human activity data in Poyang Lake in over twenty years, the evolution trend of water quality, the pollution characteristics and the severe situation were analyzed systematically, and the corresponding prevention and control measures proposed according to various pollution factors. The results show that the water quality of Poyang Lake is in the middle nutritional level with the trend of decreasing in recent years. In terms of spatial distribution of water quality, the pollution level in south area is more serious than that in north area, and in terms of the temporal distribution, the high water period is better than that in low water period. The serious water pollution, the huge population pressure and the construction of ecological and economic zones and water control projects yield great potential threats to the water quality in Poyang Lake. The key measures to solve the water pollution problem in Poyang Lake were proposed, such as optimizing the Three Gorges Reservoir and the regulating scheme in "Five Rivers" basin, adjusting the industrial structure and reducing the pollutant discharge, and establishing basin-specific environmental access thresholds and pollutant discharge standards.