A backlight module, comprising a light guide plate (24) and a light source device (27) used for providing the light guide plate (24) with a light. The light source device (27) comprises a circuit board (271) and an LED light (272) electrically connected to the circuit board (271). The LED light (272) is arranged outside of a lateral surface of the light guide plate (24). The circuit board (271) is arranged parallel to the light guide plate (24). Also, a part of the circuit board (271) is pressed on the surface of a side of the light guide plate (24). A display device (20), comprising a frame (21) and, mounted on the frame (21), a liquid crystal screen (22) and the backlight module. The circuit board (271) and an optical film (23) share a part of a thickness space, thus allowing a back panel at a light incidence side of the backlight module to be flush and non-bulging, improving the exterior design of the backlight module, and reducing the thickness of the module.