A method for calculating 19 biological parameters associated with the light absorption of human skin by means of a mathematical model. This method establishes a relevance between the skin spectrum and the biological parameters associated with light absorption in the epidermal/dermal layer of skin, by establishing two levels of analytical models, namely, a skin spectral analysis model and a mathematical model of biological parameters in the skin associated with the light absorption, achieves virtual spectrums which are stimulated by a set of skin parameters, and then performs optimization iteration by information processing technology using the virtual spectrums and the actual spectrums, to find a set of optimized results which meets a specific standard of the goodness of fit, thus reaching the goal of quantitatively analyzing biological parameters associated with the light absorption in human skin.