The present invention relates to a backlight module including: a rear plate; a reflective sheet disposed on the rear plate; a glass substrate disposed on the reflective sheet, a surface of the glass substrate facing the reflective sheet being formed with an optical dot structure layer and another surface of the glass substrate acting as a light exiting surface; and a backlight source disposed at a side of the glass substrate. The backlight source and the glass substrate have a first polarizer disposed therebetween and thereby light emitted from the backlight source becomes a polarized light after passing through the first polarizer, subsequently enters into the glass substrate and then exits out from the light exiting surface after being reflected by the optical dot structure layer. Moreover, the present invention further discloses a liquid crystal display device including the above backlight module.