The utility model discloses a backlight module comprising a frame, a light guide plate and an optical film layer. The side walls of the frame enclose a bearing zone. The light guide plate and the optical film layer are disposed in the bearing zone. The optical film layer locates on the emergent side of the light guide plate. At least one pair of opposing side walls of the frame are provided with limit grooves respectively. The optical film layer is provided with limit protrusions which are in one-to-one correspondence to the limit grooves and which fasten to one another. During assembly of the backlight module, the light guide plate and the optical film layer are sequentially placed in the bearing zone, the limit protrusions of the optical film layer extend into the limit grooves of the frame, and thus the optical film layer is limited both vertically and horizontally. Therefore, the optical film layer of the backlight module is prevented from shedding from the frame. In addition, the utility model provides a display device effective in displaying.