The SO2 catalytic reduction was carried out under the condition of high pressure in this study. Sn-Zr based oxide and CO were used as the catalyst and reducing agent for the reduction of SO2 to element sulfur, respectively. In order to compare the reactivity with the pressure on the catalytic process, the reactivity tests were performed under the conditions of atmospheric pressure and 20 atm. SO2 conversion, the element sulfur yield and COS selectivity were also compared with changing the reaction temperature, CO/SO2 mole ratio and the space velocity(GHSV). SO2 conversion increased with increasing temperature and CO/SO2 mole ratio under the condition of atmospheric pressure and element sulfur yield decreased due to the production of COS by the series reaction of CO and the produced sulfur. However, high SO2 conversion and high element sulfur were obtained under the condition of 20 atm. It was concluded that COS decreased due to the condensation of the produced element sulfur under the condition of high pressure. Therefore, the high sulfur yield for SO2 catalytic reduction could be profitably obtained under the condition of high pressure.