Abstract: Based on the features of the major water source areas in the lower reaches of the Changjiang River and characteristics of water pollution accidents,a water flow and quality prediction model,one-dimensional for the whole and two-dimensional for subsection,was established,using the Jiangsu section of the Changjiang River as a case for study,and further on,a risk early warning model was built up for water source areas in that region,thus realizing dynamic simulation of processes and early warning of water pollution risks of fixed and moving sources.By combining the water quality prediction model,risk early warning model,GIS,remote controlling and automation technology,a water source sudden water pollution incident early warning system was developed.The system may accurately and visually display scopes and trends of the impacts of water pollution accidents and provide scientific basis for decision-making in risk early warning and addressing water pollution accidents in water source areas.