A backlight module includes a light source array, a reflector module, and an optical film. The light source array includes a plurality of light sources. The light emitted from the light source can be refracted by the lens unit to obtain a specific light-output angle and uniformity. The reflector module includes a plurality of reflector units. Each reflector unit includes a flat portion, a first wall portion, and a corner wall portion, which have structures and arrangements designed to enable the light source to achieve a display effect of less shadows and better contrast.