Abstract: A new method for determination of tin and lead content in TDI-reduction catalyzer by XRF was developed and evaluated. We prepared for standard sample, made the choice of peak on different working conditions, and the method of deducting background. It is concluded that XRF could determine SnO₂ and Pb content simultaneously while the sample was scatheless. Under the best working condition, 10 times determination was done, The result is that the relative standard deviations of Pb is 0.37%, and SnO2 is 061%.