Abstract: With the intensification of human activities and the impact of climate change, the conditions of the inflow of the five contributing rivers(Ganjiang River, Fuhe River, Xinjiang River, Raohe River and Xiuhe River) and the main stream of the Yangtze River have changed greatly, and the hydrological relations among rivers and lakes have also changed. This paper constructed one-dimensional and two-dimensional coupled hydrodynamic model of the Yangtze River-Poyang Lake-Five River tails, simulated the outflow of Poyang Lake under extreme combined scenarios of the five rivers inflow, the Yangtze River inflow and interval rainfall.The results could provide technical support and method reference for flood control, drought relief and water resource management decision-making of the Poyang Lake.