Abstract: The semi-solid slurry of A356 aluminum alloy was prepared by inclined cooling plate method. The influence of pouring temperature, flow distance of liquid alloy and inclined angle on the solidification microstructure of slurry was investigated. The results show that the primary phase morphology in A356 alloy becomes from dendrite shape to spherical agglomerate, blocky shape or rose-shape due to chilling nucleation and flow impact of inclined cooling plate. The lower pouring temperature, longer flow distance and smaller inclined angle are favorable for getting semi-solid alloy slurry with finer and rounder primary phase structure, but can also result in the increasing tendency of solidified shell on cooling plate or nonuniform microstructure. The semi-solid A356 alloy slurry with fine and round primary phase was obtained when the pouring temperature was 630-640 ℃, flow distance of liquid alloy was 800 mm and inclined angle was 60°.