Abstract: Porous Ce_0.5Zr_0.5O₂ solid solution support was first prepared by a co-precipitation method. Then, different concentrations of Co (10%, 20%, and 30 %) were loaded over Ce_0.5Zr_0.5O₂ by impregnation process. The fresh catalysts were characterized by some physicochemical characterizations such as N₂ physical adsorption(BET), X-ray diffraction (XRD), temperature-programmed reduction of hydrogen (H₂-TPR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The amount of deposited carbon over used catalysts was analyzed by temperature-programmed oxidation of oxygen (O₂-TPO) and thermogravimetry (TG). The catalytic performance of these Co/Ce_0.5Zr_0.5O₂ catalysts was evaluated by methane partial oxidation to produce synthesis gas. The results show that cobalt oxide is easy to be reduced to metal cobalt over Ce_0.5Zr_0.5O₂. This series of Co/Ce_0.5Zr_0.5O₂ catalysts show high activity and selectivity to H₂ and CO. It was found that loading high concentration of Co could benefit the increase in catalytic activity and ability to resist the coke.