In　this　paper,　a　fixed　bed　reactor　was　used　for　investigating　the　effect　of　SO2　on　NO　reduction　using　biomass　char　made　of　rice　husk　at　a　temperature　of　900°C,　with　an　inlet　SO2　concentration　ranging　from　400　to　2000　ppm.　The　adsorption　and　desorption　experiments　with　NO,　SO2　and　NO+SO2　on　char　were　performed　in　the　same　reactor　for　a　more　detailed　analysis.　The　results　suggested　that　SO2　showed　an　negative　impact　on　NO　reduction　by　biomass　char,　which　can　be　mainly　attributed　to　a　better　adsorption　performance　of　SO2　on　the　biomass　char　than　that　of　NO　and　a　strongly　depressed　behavior　of　SO2　on　NO　adsorption　by　competing　for　the　same　char　surface　active　adsorption　sites.　However,　the　negative　effect　of　SO2　could　get　weaken　with　the　increased　SO2　concentration.　Partially　explaining　the　situation　was　the　increased　proportion　of　the　char　surface　carbon-oxygen　complexes　that　can　accelerate　the　production　of　CO　with　the　presence　of　SO2.　©　2023　The　Authors.