Abstract: Benefits of flood control engineerings system is very difficult to calculate,and in many cases,they are only obtained by rough estimating.Hydrology,hydraulics,engineering and economic problems of the Yellow River flood control engineerings system are discussed.A systematic calculating model is developed to solve these problems.A 2-dimensional flood routing model is also developed to study flood status in flooding area of the lower Yellow River flood protected zone (120 000 km²).According to real conditions of the protected zone,the estate data,flood loss rate,terrain and obstruction parameters and so on are discussed.The cases studies show that the results are reasonable and the model is effective.