The invention relates to the technical field of display, and discloses a backlight module and a display device. The backlight module comprises a back plate with an accommodating groove, a reflecting piece positioned in the accommodating groove, and a light guide plate positioned above the reflecting piece. An opening opposite to the light guide plate and not smaller than a surface corresponding to the light guide plate is arranged on the side wall of the accommodating groove. The backlight module further comprises an opening retaining plate, and the opening retaining plate is detachably connected with the back plate and can shield the opening. The opening retaining plate of the backlight module is demounted from the back plate to pull the light guide plate out of the opening of the side wall of the back plate, so that workload for reworking and reassembly of the display device can be reduced, reworking and reassembly efficiency is improved, and product cost of the display device is reduced.