A display device and a driving method thereof are disclosed, the driving method includes: setting average values of a first component, a second component, and a third component of a first frame display image to be equal to a second average value, and setting the average values of both the first component and the third component of a second frame display image to be equal to a third average value, and setting the average value of the second component to be equal to a set average value; adjusting lightness of a backlight module according to the average values of the first component, the second component, and the third component corresponding to the original display image, the first frame display image, and the second frame display image.