The　steel　slag　contains　a　lot　of　alkali　metal　oxides,　which　makes　it　have　the　potential　as　flue　gas　desulfurization　agent.　The　modification　of　steel　slag　for　dry　flue　gas　desulfurization　is　of　profound　significance　for　ecological　environment　protection　and　resource　conservation.　In　this　work,　the　steel　slag　was　modified　by　adjusting　the　composition　of　metal　oxide　to　improve　its　desulfurization　performance.　Firstly,　the　promotion　effect　of　the　main　metal　oxides　Fe2O3,　Al2O3,　MgO　and　MnO　in　the　chemical　composition　of　steel　slag　on　CaO　and　dry　desulfurization　of　steel　slag　was　confirmed,　and　then　the　composition　of　the　main　metal　oxides　of　steel　slag　was　regulated　by　acid　and　alkali　treatment　to　improve　the　desulfurization　performance.　XRF,　XRD,　XPS,　SO2-TPD　and　other　test　methods　were　used　to　study　the　reasons　for　the　improvement　of　desulfurization　performance.　The　results　show　that　after　modification,　some　metal　ions　existing　in　the　same　structure　of　solid　solution　are　separated　into　metal　oxides.　The　content　of　lattice　oxygen　and　adsorbed　oxygen　on　the　surface　of　steel　slag　increases,　the　proportion　of　lattice　oxygen　increases,　and　the　physical　and　chemical　adsorption　capacity　of　SO2　is　enhanced.　When　the　pH　value　is　13,　the　best　effect　is　achieved,　and　the　desulfurization　rate　can　reach　93%.　©　2023　Cailiao　Daobaoshe/　Materials　Review.　All　rights　reserved.