The present disclosure provides a backlight driving method and device and a display device, wherein the backlight includes a plurality of backlight scanning areas, each luminous body corresponding to each backlight scanning area is driven independently, including: acquiring display gray scale of a current frame of image and that of a previous frame of image in a backlight scanning area; determining a first backlight duty ratio according to the display gray scale of the current frame and that of the previous frame; if black frame insertion time in the first backlight duty ratio is smaller than a first black frame insertion time, acquiring a second backlight duty ratio, wherein black frame insertion time in the second backlight duty ratio is not less than the first black frame insertion time; determining drive timing of the luminous bodies in the current frame according to the second backlight duty ratio.