Disclosed are a backlight module and a display device. The backlight module includes a backplate, a led-bar, a light guide plate and an optical sheet group; wherein the led-bar includes a plurality of light sources disposed towards the light entrance surface of the light guide plate; the light exit surface and the light entrance surface of the light guide plate are adjacent; a portion of the light exit surface of the light guide plate near the light entrance surface is provided with a step structure in which heights of steps gradually decrease in a first direction; the optical sheet group includes a plurality of optical sheets stacked on the side where the light exit surface of the light guide plate is located, and each of the optical sheets is fixed to a corresponding step in the step structure.