Surface　aluminizing　technology　is　a　cost-effective　method　which　can　improve　the　high-temperature　steam　oxidation　resistance　of　substrate　alloys　without　worsening　their　mechanical　performance.　Aluminide　coatings　were　obtained　on　P92　steel　surface　by　low-temperature　pack　cementation　and　vapor　aluminizing　process.　The　oxidation　behavior　of　the　aluminide　coatings　in　saturated　steam　at　650　was　investigated　by　oxidation　weight　increase　method,　SEM　together　with　XRD　analysis.　Results　show　that　the　P92　steel　has　a　poor　oxidation　resistance.　A　double-layered　oxide　scales　consisting　of　nodular-typed　Fe-rich　outer　layer　and　FeCr2O4　inner　layer　formed　on　P92,　and　the　outer　Fe-rich　oxide　film　begin　to　peel　off　after　300　h.　As　for　low-temperature　pack　cementation　aluminizing,　a　thin　β-FeAl　layer　grows　on　P92　steel,　and　an　extremely　thin　(2O3　scale　forms　on　β-FeAl　layer.　A　single　Fe3Al　layer　forms　after　vapor　aluminizing.　A　mixed　oxides　conpose　of　an　outer　Fe3O4　+Fe2O3　of　about　1.3　μm　and　an　inner　Al2O3　scale　after　500　h　oxidation.　Aluminide　coatings　prepared　on　P92　steel　through　both　low-temperature　pack　cementation　and　vapor　aluminizing　process　can　improve　the　steam　oxidation　resistance　of　P92　steel　significantly.　©　2020,　Editorial　Office　of　CHINA　SURFACE　ENGINEERING.　All　right　reserved.