A color gamut mapping method based on a color gamut of a source image is disclosed. The method comprises: (a) inputting a source image, measuring a grayscale value of each of color sub-pixels corresponding to each pixel point; (b) determining multiple preset target pixel points on the source image based on the grayscale value of each of the color sub-pixels; (c) calculating multiple coordinate values in an uniform chromaticity space corresponding to each of the multiple preset target pixel points; (d) determining a color gamut of the source image based on the multiple coordinate values; (e) extracting a color gamut boundary of a target device to obtain a color gamut; and (f) performing a color gamut mapping between the source image and the target device. In a transfer and reproduce process of image colors, the loss is reduced, gamut mapping effect is better, and effectively reduce the amount of calculation.