A backlight, a control method of the backlight, and a display device are provided. The backlight includes a plurality of light-emitting modules arranged in an array. Each of the light-emitting modules includes a light-emitting unit and a control circuit. The control circuit includes n branches, a controller, and a current module. Each branch of the n branches is connected in series with the light-emitting unit and the current module. Each branch is provided with a switch, and the controller is separately connected to the switch on each branch.