A backlight module includes a light guiding plate with a light incident lateral surface. Pluralities of V-shaped grooves are disposed on the light incident lateral surface, the grooves are disposed along the light incident lateral surface in a direction of width of the light guiding plate with equal interval, and light emitting modules are disposed respectively on the opposite position of the slopes of the grooves correspondingly. The present invention further provides a liquid crystal display device equipped with the backlight module. The backlight module and the liquid crystal display device equipped with the backlight module can improve the brightness of the backlight module efficiently.