Abstract: Catalytic reduction of SO2 to elemental sulfur can not only remove SO2 pollution but also obtain elemental sulfur. The reaction process and catalytic mechanisms for the reduction of sulfur dioxide to sulfur are discussed in detail when carbon，hydrogen，methane and carbon monoxide are used as the reductant respectively. Merits and demerits of different reductant are compared. Carbon thermal reduction of SO2 and direct catalytic reduction of SO2 by CO in flue gas are proposed to be the important development direction.