Abstract: A backlight module is disclosed in the present invention. The backlight module comprises a light guide plate and a light source. The light guide plate comprises a light incident surface, and the light source is disposed adjacent to the light incident surface. The backlight module further comprises a protruding part, which abuts against the light incident surface to define a distance between the light source and the light incident surface. The present invention further discloses a liquid crystal display (LCD) device, which is provided with the aforesaid backlight module. Because the backlight module of the present invention is provided with a protruding part that effectively defines a distance between the light source and the light incident surface of the light guide plate, the light coupling efficiency of the backlight module is remarkably optimized.