Climate change combined with more frequent human activities have strongly disturbed the natural water cycle. In addition, the increasing population and social wealth in flood protection zone caused new challenges for flood control for large rivers under the changing environment. This article reviewed the challenges that the flood control for large rivers is facing the two key challenges as "retain or release" and "protect or abandon" problems. Furthermore, some key techniques utilized for decision making were presented, including: building of optimization model, multi-objective problem solving,balance decision-making techniques, as well as high precision prediction of basin runoff and sediment dynamical simulation supported by dynamic calculation of flood "retain or release". In the end,the application of related technologies was further verified with typical case studies.