AlxGa1-xAs Auger sensitivity factors have been determined by using PHI 610 scanning Auger microprobe with pure elemental standards Al, Ag and matrix GaAs. The quantitative results of AlxGa1-xAs measured by the present method are in very good agreement with that by X-ray double crystal measurement. It is shown that by using sensitivity factors obtained from the self-instrument, the accuracy of the quantitative AES analysis can be considerably improved compared with that using elemental relative sensitivity factors given by the PHI handbook or internal standard method.