The Cu1Zr1Ce9Oδ catalysts synthesized with coprecipitation method were used into the selective CO oxidation in hydrogen-rich gas. The adsorbed species and the intermediates on Cu1Zr1Ce9Oδ catalysts were examined by in-situ diffuse reflectance FTIR spectroscopy (in-situ DRIFTS) technique. It was found that hydrogen, oxygen and CO in the feed stream were adsorbed competitively at the same adsorption sites on the surface of Cu1Zr1Ce9Oδ catalysts. The pretreatment with hydrogen caused the deep reduction of Cu+ species to Cu0 species and decreased the capacity of CO adsorption on the catalyst surface. The Cu1Zr1Ce9Oδ catalyst pretreated with oxygen offered more active oxygen species and inhibited the deep reduction of Cu+ species. The helium pretreatment only purified the surface of Cu1Zr1Ce9Oδ catalyst. Two IR bands at 2 938.7 and 2 843.8 cm-1 due to bridged formate and bidentate formate species appeared at 180 ℃. The active oxygen anion of Cu1Zr1Ce9Oδ catalyst could react with CO and produce carbonate species at room temperatures. The carbonate and formate species occupied the adsorption sites and deteriorated the catalytic performance of Cu1Zr1Ce9Oδ. Flushing the Cu1Zr1Ce9Oδ catalyst with helium at 300 ℃, the bidentate formate species on the catalyst surface decomposed to monodentate carbonate species and then further decomposed to CO2, which could release the adsorption sites and restore well the catalytic activity.