A backlight module including a light guide plate, a light source, a diffuse reflector and a light-splitting film is provided. The light guide plate has a light incident surface, and a light-emitting surface and a bottom surface which are respectively connected to the light incident surface and opposite to each other. The light source is disposed on one side of the light incident surface of the light guide plate. The diffuse reflector is disposed on one side of the bottom surface of the light guide plate. The light-splitting film is disposed between the light guide plate and the diffuse reflector. The light-splitting film has a substrate and a plurality of first optical microstructures disposed on one side of the substrate. An extending direction of the first optical microstructures intersects with the light incident surface of the light guide plate. A display apparatus using the backlight module is also provided.