This invention is related to a backlight module for a liquid crystal display device and, more particularly, to a backlight module having a frame with an impact damping design. The impact damping design can damp impact or absorb impact energy, and thereby protect the important components of the backlight module, such as the lamp or the light guide plate. The backlight module includes a light guide plate that has at least one protrusion located at its periphery, and a frame that has at least one indentation part located at its inner side edge. The indentation part engages with the protrusion to fix the light guide plate, and has at least one opening nearby to damp an impact to the indentation part.