In this paper a combined spectrophotometric method is used to analyzed As-S chalcogenide thin films. This method is based on the simultaneous interpretation of experimental data corresponding to the reflectance from the ambient side, reflectance from the substrate side and transmittance of the chalcogenide films deposited onto the glass substrate. It is shown that this method is usable for the optical characterization of the chalcogenide films even when these films exhibit an inhomogeneity formed by a refractive index profile. Within this method our dispersion model of the optical constants of amorphous materials is used. This means that the values of the dispersion parameters determining the spectral dependences of the optical constants of the As-S chalcogenide material are evaluated. In the paper the advantages of the combined method mentioned are discussed from the practical point of view.