Although　PtAl　is　an　attractive　thermal　barrier　coating　(TBC),　the　key　problem　is　to　adjust　the　correlation　between　the　oxidation　resistance　and　mechanical　properties.　Here,　we　apply　the　first-principle　calculations　to　investigate　the　oxidation　mechanism　of　PtAl　coating　and　explore　the　influence　of　alloying　elements(Y,　Cr　and　Si)　on　the　oxidation　resistance　of　PtAl　coating.　We　further　study　the　influence　of　Cr　concentration　on　the　elastic　modulus　and　brittle-or-ductile　behavior　of　PtAl.　It　is　found　that　0　prefers　to　occupy　the　center　of　Pt　tetrahedron.　Compared　to　Y-dopant,　Cr-dopant　and　Si-dopant　enhance　the　oxidation　resistance　of　PtAl　coating　because　the　charge　interaction　of　Cr-O　and　Si-O　is　stronger　than　that　of　the　AI-0　atoms.　In　particular,　the　Cr　element　effectively　improves　the　shear　deformation　resistance　and　elastic　stiffness　of　PtAl.　With　increasing　Cr　concentration,　the　formation　of　Cr-Al　bond　enhances　the　elastic　stiffness　and　shear　deformation　resistance　of　PtAl.　Therefore,　our　results　predict　that　Cr　is　a　useful　element　to　improve　the　overall　performance　of　PtAl　thermal　barrier　coating.