A backlight module includes an optical plate, a light source, and at least one optical film. The optical plate includes a light-emitting surface, a bottom surface and a side surface. The light source faces to the bottom surface or the side surface. The optical film is disposed above the light-emitting surface and includes a main body and at least one refractive part disposed on an end surface of the main body. The refractive part includes a plurality of microstructures and a substrate. The substrate is adhered to the end surface, and the microstructures are distributed in the substrate.