On the basis of summarizing relevant literatures at home and abroad, the related concepts, sedimentary dynamics and sedimentary characteristics of sandy debris flow are systematically sorted out, and the controversial issues are discussed. Sandy debris flow is a kind of Binghan plastic fluid with medium to high detrital concentration (volume concentration ranges from 25% to 95%) and low mud matrix content (minim volume concentration 0.5%). It represents a series of debris flow from cohesive to no cohesive flow without obvious turbulence. Sandy debris flow deposits are representing by massive sandstone, sandstone with inverse floating mud clasts. Slump shear structures and liquefied swirly patchy texture can be observed occasionally. The formation of sandy debris flow mostly undergoes the orderly evolution process of sliding slipping sand debris flow turbidity flow. Hydroplaning and basal shear wetting are the main mechanisms to overcome shear friction between sandy debris flow and the base. Fluid strength is an important reason to overcome the dilution of the overlying ambient water. Debris flow has the characteristics of preferential deposition and consolidation of the head and the edge, thus controlling the overall settlement of the fluid. Sandy debris flow is one of the main reasons for the formation of deep- water massive sandstone, which is widely developed in a relatively low fluid efficiency deep water gravity flow deposition environment.