The invention provides a color gamut expansion system and method for realizing color gamut expansion when an image is transferred from a first color gamut to a second color gamut by generating a standard color comparison table of image colors in the first color gamut and an image colors in the second color gamut. The color gamut expansion system comprises a first conversion module for converting a color system of the first color gamut into a first conversion color gamut; a second conversion module for converting a color system of the second color gamut into a second conversion color gamut; a coordinate point corresponding module for calculating coordinate points, corresponding to respective coordinate points in the first conversion color gamut, in the second conversion color gamut according to a corresponding algorithm; a correspondence table generating module for generating a correspondence table for the conversion from the first conversion color gamut to the second conversion color gamut; and a standard color comparison table generating module for generating a standard color comparison table according to the correspondence table. The color gamut expansion system and method can keep the output results of the image on different displays, obtain an effect of the color gamut expansion, increase processing speed and reduce the power consumption of a CPU.