Abstract: Aimming at the problem of the erosion of parts of seacoast after the variation of flow and sediment in the Yellow River estuary,we research on the relationship between the epeirogenesis of seacoast and the variation of flow and sediment using the methods of f ield data analyses and theoretical study.The research results show that the flow and sediment coming from land is the foundation of the epeirogenesis of seacoast,the bigger the incoming flow and sediment is the bigger the area of the epeirogenesis.After the variation of flow and sediment,the epeirogenic area of seacoast reduces greatly because the decrease of the incoming flow and sediment The atrophy of tail channels affects greatly on epeirogenesis of seacoast,the heavier the atrophy of tail channels,the less advantageous the epeirogenesis of seacoast.By using the methods of the regress analysis,the synthetical critical mathematical relationship of the epeirogenesis of seacoast is established It provides reference usage during the process of controlling the incoming flow and sediment to defend seacoast in the Yellow River estuary.