A backlight module includes a light-guiding plate, a plurality of reflection spots, and a light source. The reflection spots are disposed on a back surface of the light-guiding plate. Light emitted by the light source enters the light-guiding plate through a light input side surface of the light-guiding plate, and is reflected by the reflection spots to emit out of the light-guiding plate through a light output surface of the light-guiding plate. The back surface includes a central portion and a fringe portion. The fringe portion extends along an edge of the back surface. The distribution density of the reflection spots on the fringe portion gradually decreases in a direction from the central portion toward the fringe portion.