The invention relates to an image color saturation adjustment method and system. The method comprises the following steps: acquiring a currently displayed image, and calculating the maximum brightness value, the minimum brightness value and the average brightness value of the image; establishing a corresponding relationship between brightness values and color saturations of the image according to the maximum brightness value, the minimum brightness value and a plurality of preset color saturation levels, and searching the corresponding relationship between the brightness values and the color saturations for a target brightness value interval where the average brightness value exists; and acquiring a target color saturation corresponding to the target brightness value interval according to the corresponding relationship, and adjusting a color saturation of the image to the target color saturation. The method and system provided by the invention has the advantages that color saturation values matched with various brightness value intervals of the current image can be accurately acquired, so that the adjustment accuracy is high, and the adjustment effects are good.