A method for adjusting saturation of an area of an image is disclosed. The method includes calculating a deviation level of a pixel in the area of the image and calculating a modified saturation value of the pixel in the area of the image according to the deviation level of the pixel in the area of the image and an original saturation value of the pixel in the area of the image. The deviation level indicates brightness differences of the brightness values among the pixel and a pixel set in a vicinity of the pixel in the area of the image. The pixel set includes pixels in the vicinity of the pixel of the area of the image.