According to the chromatic′s theory, color sensitive functions of object, light source and human eyes are defined in the widely used CIE1976L*a*b* color space and color difference［1］. Mathematics formulae are deduced. The three kinds of color sensitive functions are studied systematically and comprehensively in the whole color space. The general law of color sensitive functions are concluded. Mathematics models of the three kinds of color sensitive function can be used in some fields such as computer color matching, making light source and simulation of human eyes of colorimeter.