Abstract: Coal gangue is a kind of black and gray rock with low carbon content associated with coal seam in the process of coal formation. Coal gangue is a kind of hard natural ground material in essence, its compressive strength is close to gravel, its weathering resistance is worse than gravel, and its economic effect is much better than gravel. This paper mainly discusses the technical application of coal gangue instead of gravel in road subgrade engineering. Through the utilization of coal gangue, the coal gangue stock produced in the process of coal mining can be digested and utilized, and the pressure of coal gangue stock can be reduced. Second, it can effectively save the amount of gravel materials, and save related costs, and create greater economic benefits