A backlight module structure including a light guide plate and a plurality of light emitting diodes is provided. A plurality of first micro-structures and a plurality of second micro-structures are formed on the light incident surface of the light guide plate, and the first micro-structure and the second micro-structure are respectively disposed on two sides of the light incident surface and distributed along the light incident surface. The first micro-structure has a first receiving surface and the second micro-structure has a second receiving surface. The first and second receiving surfaces are faced oppositely and incline at least one inclined angle, such that the normal lines thereof are deflected to the imaginational center of the light guide plate, respectively. The light emitting diode has an emitting surface disposed correspondingly to the abovementioned the first receiving surface or the second receiving surface, and the lights of light emitting diodes enter into the light guide plate from the first receiving surfaces and the second receiving surfaces.