This overview article outlines a quantitative XPS analysis method for alloys covered with a homogeneous surface oxide film over which a contaminant carbon layer exists. The thicknesses of the surface oxide film together with the contaminant layer, compositions of the surface film and near interface region of the alloy under the surface film can be determined by this method. Moreover, a method for energy calibration of a spectrometer and a method to determine photoionization crosssections for the quantitative analysis are explained. Examples of the application of the quantitative analysis are the determination of surface compositions of Fe-base alloys under several conditions, sputter-deposited Ta-Mo alloy surfaces after mechanical polishing and immersion in a concentrated HCl solution, and meaning of the film thickness of porous corrosion products. Investigation of the origin of extremely high corrosion resistance of sputterdeposited Cr-valve metal alloys examined by the precise binding energy determination, and a non-destructive depth analysis by the angle-resolved method is also presented.