The present application discloses a display device and a driving method thereof. The method of driving the display device includes: acquiring a picture to be displayed; determining whether the picture to be displayed is a heavy-loaded picture; adjusting a first gamma voltage corresponding to the picture to be displayed to a second gamma voltage if the picture to be displayed is the heavy-loaded picture, wherein corresponding to a same gray scale, a voltage value of the second gamma voltage is less than a voltage value of the first gamma voltage; and driving the display device to display the picture to be displayed according to the second gamma voltage.