Abstract: A flood prevention system consists of embankments and dams. The optimization results are difficult to be achieved only by use of single embankment or reservoir, especially when the risk rates of various sub- systems in the flood prevention system are extremely unbalanced. Therefore, relative measures should be employed tomake thembalanced, basing on the local and actual situation. It is vital to improve the whole safety of flood prevention system. Combined with the specific conditions of Yishusi river basin, preliminary studies on risk control and optimization measures for flood prevention system were performed. Influence of different engineering and non- engineeringmeasures on single embankment and flood prevention systemwas calculated and analyzed.