1. A method for adjusting saturation of an area of an image for the image to be displayed in an electronic system, the electronic system comprising a storage unit for storing information of the image, the method comprising: calculating a deviation level of a pixel in the area of the image, the deviation level indicating 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 comprising pixels in the vicinity of the pixel of 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 to achieve saturation adjustment of the pixel in the area of the image.