Modification　of　manganese-based　selective　catalytic　reduction　(SCR)　catalyst　by　five　kinds　of　the　element　was　studied　to　improve　its　SO2　resistance.　In　this　paper,　density　functional　theory　(DFT)　calculation　was　used　to　analyze　the　effects　of　doped　atom　on　electronic　dispersion　and　crystal　structure　of　MnO2(100).　Our　result　demonstrated　that　the　doping　of　Ni,　Cr,　and　Co　could　increase　the　strength　of　Lewis　acid　sites　for　the　manganese　based　catalyst,　while　Se　and　Sn　decrease　that.　On　the　other　hand,　the　manganese-based　catalyst　modified　by　Se　and　Sn　present　better　resistance　to　sulfur　poisoning.　By　comparing　the　dissociation　energy　barrier　of　NH3　over　different　element　doped　catalyst　and　analyzing　the　partial　density　of　state　(PDOS)　for　SO2　adsorbed　on　the　catalyst,　we　found　that　Cr　could　be　as　a　potential　dopant　modifying　the　manganese　catalyst,　because　of　it　could　convert　sulfur　to　Bronsted　acid　sites　which　catalyze　NH3-SCR　through　followed　the　LH-mechanism.