通过对黄河下游洪水进行分类对比 ,系统地分析了各类洪水水沙特性、冲淤规律 ,着重强调了 1986年以来水沙冲淤特性。研究了不同含沙量级洪水对河道冲淤的影响作用。研究表明 ,一般洪水对冲淤影响最大的因素是含沙量 ,高含沙洪水是来沙量 ,低含沙洪水是来水量 Through the classification and comparison of the floods in the lower reaches of the Yellow River, the characteristics of various types of flood and sediment, scouring and silting are systematically analyzed, and the scour and silting characteristics of the water and sediment since 1986 are emphasized. The effects of different floods on the scouring and silting of the river are studied. The research shows that the most influential factor of the general flood scouring and silting is the sediment concentration, the high sediment flood volume is the sediment yield, the low sediment flood volume is the water quantity