The catalytic activity and selectivity of catalysts prepared by coprecipitation method with different precipitants, calcined temperature and the pretreatment condition with different content of Au and ZnO loading dispersed over nanoparticles TiO ₂ for CO oxidation in H ₂-rich gas was studied. The simulated material gas was used as reaction gas and the evaluation on catalytic activity of product was made through microreaction- chromatograph instrument. The catalyst was characterized by XRD and BET. The results show that the activity and selectivity of the catalysts are greatly changed with the variation of the ZnO loading, the kind of precipitant, calcination temperature and pretreatment condition; the catalyst Au(2%)/ZnO(2%) /TiO ₂ with (NH ₂)2CO as the precipitants, calcined at 300 ℃, pretreatment in H ₂ and reaction temperature for 30℃ has optimal activity and selectivity.