The quantitative surface chemical analysis of Au-Cu alloys with N (E) curve of AES was studied. As for the Auger peaks at above 100 eV, the P/B method was applied to calculate the intensities. It was found that the P/B method was insensitive to the parameters measurements, and the values obtained by this quantitative chemical analysis were in good agreement with those by the ordinarily used dN (E) /dE method. However, the Auger peaks of Cu (60 eV) and Au (69 eV) at below 100 eV overlap, so that the peak fitting method was used to determine the surface compositions of the samples. The values from N (E) curves were in good agreement to those from dN (E) /dE curves also in this case.