The invention provides backlight and a control method and a display device thereof, and the backlight comprises at least two luminous sources of which the color temperatures are different; a control module used for controlling drive current of a luminous source of each color temperature so as to adjust the color temperature of the backlight. According to the backlight disclosed by the invention, adjustable color temperature of the backlight can be realized by arranging the at least two luminous sources of which the color temperatures are different, and by respectively controlling the drive current of the luminous source of each color temperature through the control module, when the backlight is applied to a liquid crystal display, the color temperature of the liquid crystal display can be changed under the situation that the transmittance of a liquid crystal display panel is not changed, and the influence on the image quality can be avoided.