In a complete uniform solid solution of a binary alloy, a theoretical method for constructing a very quantitative calibration line for an AES experiment has been developed. In the method, the following are considered: (i) attenuation of a primary beam, (ii) the effects of backscattered electrons and forwardscattered electrons both from solute and base metals, and (iii) true escape lengths of any electrons. Results of calculations are applied for Ag‐Au, Mo‐W, and Be‐Cu systems.