A backlight module installs a light guide plate, a plurality of optical films, and a liquid crystal display panel in order on an emergent plane of a light source, wherein the light guide plate forms more than one hollow layer within an incident side to an effective light emitting area, such that the hollow layer of the light guide plate changes the light path of the light of the light source to effectively distribute and evenly emit the light towards each optical film. As a result, the dark band in each light source can be eliminated, the issue of having dark and bright bands according to the prior arts can be overcome effectively, and the light performance including luminance and evenness can be enhanced.