The　adsorption　of　SO2　on　the　Ni(001)　surface　has　been　studied　by　using　cluster　models　with　density　functional　theory　(DFT)/B3LYP　method.　The　optimization　of　geometry,　calculation　of　the　adsorption　energy,　net　charge　and　density　of　state　have　been　performed.　For　Ni(100)　surface,　the　most　stable　structure　is　that　SO2　is　absorbed　with　its　molecular　plane　nearly　parallel　to　the　surface　and　the　S　atom　located　in　the　bridge　site.　This　result　is　in　good　agreement　with　that　in　experiment.　The　interaction　of　sigma-pi*　between　the　3d　orbital　of　Ni　and　SO2　pi*　orbital　leads　to　the　decomposition　of　SO2　molecule.