The damage profile of ion implanted silicon can be calculated from the spectroscopic elli-psometric data as well as the optical constants of crystalline and ion implanted amorphous state of silicon by means of optimization with a multilayer model. We measured the ellipsometric spectra and optical constants of ion implanted samples in the spectral range from 2.1 to 4.6 eV In the sense of optical characteristics, the degree of damage is defined using complex refractive index. We performed the calculation of damage profiles of 40 keV As+ implanted Si 〈111〉 at dosage of 4×1013 and 1.4×1014 ion cm-2, respectively, on the basis of simulated tests. The depth profiles of damage were obtained and compared with the experimental results of He+ back-scattering. The method of multilayer analysis can also be used to determine the profiles of other parameters of interest from optical spectra as long as the parameters markedly influence the optical response and do not depend upon the photon energy.