The　iron　and　steel　industry　(ISI),　the　second　largest　carbon　emitter,　produces　16%　of　China＇s　CO2　emissions,　and　its　decarbonization　will　therefore　play　an　important　role　in　achieving　the　goal　of　carbon　neutrality.　This　study　identifies　underlying　low-carbon　transition　pathways　of　the　ISI　towards　2050,　through　investigating　macro-level　mitigation　policies　and　technological　advances.　An　integrated　assessment　model　that　integrates　a　top-down　CGE　method　and　a　bottom-up　objective　planning　method　was　constructed.　The　results　show　that　the　combination　of　mitigation　policies　and　technological　measures　would　substantially　reduce　CO2　emissions　in　the　ISI,　with　the　remaining　140　Mt　to　520　Mt　by　2050.　Carbon　mitigation　in　ISI　in　the　short　term　mainly　benefits　from　the　technology　retrofitting,　the　reduction　of　steel　demand,　which　accounts　for　17.8　%　and　32.1　%,　respectively.　Breakthrough　technologies　of　scrap-based　electric　arc　furnace　(EAF),　hydrogen-based　direct　reduction　(HDREAF)　and　carbon　capture　and　storge　(CCS),　would　play　a　fundamental　role　in　reducing　the　CO2　emissions　especially　after　2030,　contributing　to　32.1　%,　16.0　%　and　13.8　%　of　emission　reduction,　respectively.　Of　the　41technologies　assessed,　8-key　technologies　jointly　mitigate　over　55%　of　CO2　emissions.　The　cost-effectiveness　and　mitigation　potential　of　technologies　would　provide　reference　to　policymaker　for　the　mitigation　in　China＇s　ISI.