Ni/ZrO2 catalysts were prepared by the incipient-wetness impregnation method and were investigated in activity and selectivity for the selective catalytic methanation of CO in hydrogen-rich gases with more than 20 vol%CO2.The result showed that Ni loadings significantly influenced the performance of Ni/ZrO2 catalyst.The 1.6 wt%Ni loading catalyst exhibited the highest catalytic activity among all the catalysts in the selective methanation of CO in hydrogen-rich gas.The outlet concentration of CO was less than 20 ppm with the hydrogen consumption below 7%.at a gas-hourly-space velocity as high as 10000 h-1 and a temperature range of 260℃ to 280℃.The X-ray diffraction(XRD)and temperature programmed reduction (TPR)measurements showed that NiO was dispersed thoroughly on the surface of ZrO2 support if Ni loading was under 1.6 wt%.When N-10ading was increased to 3 wt%or above.the free bulk NiO species began to assemble,which was not favorable to increase the selectivity of the catalyst.