A backlight module includes a back frame, a light guide plate and a cushion disposed inside the back frame. The back frame includes a base and side walls perpendicular to the base. The cushion is arranged on an area between one of the side walls of the back frame and the LGP, used for fixing the LGP inside the back frame. Air chamber is disposed inside the flexible cushion. At least one exhaust vent is disposed on a non-contact outer wall of the cushion. The air chamber communicates with the outside air via the exhaust vent, and the cushion is fixed on one of the side walls of the back frame. The backlight module is capable of stabilizing an LGP on its position when bearing instantaneous impact forces. Besides, there is enough room for the LGP to swell without being intervened by the backlight module.