A method and a device for adjusting contrast are provided. The method includes: acquiring a corresponding grey-scale image of a current image; dividing the grey-scale image to obtain a plurality of divided regions; calculating JND values corresponding to the divided regions based on an area of each of the divided regions; and calculating a target contrast based on the JND value of each of the divided regions and a background brightness of the current image; adjusting the contrast of the current image based on the target contrast and a predetermined condition.