Backboard, backlight module, assembling method of backlight module and display device

The invention discloses a backboard, a backlight module, an assembling method of the backlight module and a display device and relates to the field of display. The backboard, the backlight module and the display device are low in manufacturing cost and easy and convenient to assemble. The backboard comprises a backboard body and a backboard side wall vertically arranged at one end of the backboard body. The backboard further comprises a backboard supporting portion. The backboard supporting portion is arranged at the upper end of the backboard side wall. The lower surface of the backboard supporting portion is pressed to cover a light guide plate in the backlight module and an optical film. A display panel is arranged on the upper surface of the backboard supporting portion.