Bottom-block Scour is a typical phenomenon of hyper-concentrated floods occurred in the Little-North Reach of Yellow River and its tributary-Weihe River downstream. It often caused severe erosion in the river bed, swing and migration of mainstream, have a huge impact on flood control. This paper review the research progress of our research team in the past decades. Through soil mechanics test, the mechanics characteristics of soil in the Little-North Reach of Yellow River is studied in detail, which explain the mechanical reason of fine sediment was scoured by block shape. Also a detailed analysis for the adjustment rule of cross section during the Bottom-block Scour period was taken by digging deep into the original observation data. Using the theory of transient flow, the critical discriminant formula of the Bottom-block Scour occurred condition is established, and based on the results of successful simulate the phenomenon of Bottom-block Scour, the key parameter of the formula is determined. On the basis of damage mechanism study and historic data analysis, the countermeasures were proposed for the Bottom-block Scour.