[en] Complete text of publication follows. X-ray photoelectron spectroscopy (XPS) has been a conventional surface analysis tool. In recent years quantification of nano film thickness with XPS has been discussed. Considering the fact that the analysis rely only on the peak intensity, it would lead a great uncertainty. Therefore a universal analysis strategy has been proposed by Tougaard when an exponential in-depth distribution is supposed. This algorithm can be applied for the determination of the in-depth concentration distribution within the outermost few nanometers of the surface. In this work, we propose a more elaborate and convenient algorithm for quantification of the thickness of the nano films on the substrate. The alternative method is based on the relation between the kinetic energy of photoelectrons generated in a film and the film thickness. The XPS spectrum is formed by overlapping the emission spectra from different generation depths of signal electrons; these electrons suffer energy losses during their travel to the surface. Therefore, the deeper depth layer will give more contribution to the spectrum intensity at lower kinetic energies. Although the total intensity of the spectrum increases with the film thickness, the thicker film would have more intensive inelastic background at certain energy, E, when the signal peak intensity is normalized. A relationship between background intensity and the film thickness may thus be derived. As a test, a W/SiO2 overlayer sample was investigated. Theoretical evaluation of the spectra is compared with the experimental result (see Fig. 1). We found, that our method estimate the film thickness with reasonable well