Abstract: A chemometrics method of robust regression analysis (RRA) applied to spectrophotometric determination of components in a binary system is reported in this paper.Both Pb and Ce are reacted with dibromo-p-methyl-methylsulfonazo (DBM-MSA) to form color complexes,having similar absorption spectra which were seriously overlapped each other.The absorption peaks are located at 640 nm with molar absorptivity 7.31×104L·mol-1·cm-1 for Pb and at 642 nm with molar absorptivity 7.80×104L·mol-1·cm-1 for Ce,respectively.By using the RRA method,the absorption spectra were resolued and Pb and Ce determined simultaneously without separation.Beer′s law was obeyed in the range of 0-9 μg/25 mL for Pb and 0-11 μg/25 mL for Ce.The method has been applied to the analysis of simulated samples and SRM of steels,the results were compared to those obtained by the Artificial Neural Network-BP method,showing that both the methods gave consistent results.