Backlight module and display device

The utility model discloses a backlight module and a display device. The backlight module comprises a back plate, a light guide plate and a light guide plate, wherein the back plate comprises a firstbottom wall and a first side wall arranged on the first bottom wall; the light guide plate is located between the two oppositely-arranged first side walls; the positioning device is arranged between the light guide plate and the first side wall so as to position the light guide plate, and the positioning device can adjust the size according to the gap between the light guide plate and the first side wall so that the positioning device can be matched with the gap. According to the backlight module, the temperature environment of the display device in the non-working state and the temperature environment of the display device in the working state can be considered at the same time, the problem of optical unevenness caused by expansion of the light guide plate in the working state is avoided,the problem of diaphragm