In　this　study,　the　oxidation　behavior　and　mechanism　of　AlxCoCrFeNi1.5Ti0.1　(x　=　0,　0.25,　0.5,　0.75,　1.0)　high-　entropy　alloy　(HEA)　coatings　at　high　temperatures　ranging　from　700　degrees　C　to　900　degrees　C　were　investigated.　The　microstructure　and　oxidation　products　of　the　HEA　coatings　were　characterized　with　scanning　electron　microscopy　(SEM),　energy-dispersive　spectroscopy　(EDS),　and　X-ray　diffraction　(XRD).　In　order　to　elucidate　the　effect　of　Al　content　on　the　oxidation　behavior　of　HEA　coatings,　a　novel　oxidation　kinetic　model　modified　by　Al　content　was　developed.　The　results　indicate　that　the　oxidation　weight　gain　of　the　HEA　coatings　generally　follows　a　parabolic　law.　With　the　increase　of　Al　content,　the　microstructure　of　HEA　coatings　transforms　into　a　dual-phase　structure　(FCC　and　BCC)　containing　new　BCC　phases.　When　the　HEA　coatings　are　composed　of　the　dual-phase　structure　(FCC　and　BCC),　the　oxidation　process　of　the　coatings　is　primarily　inhibited　by　the　diffusion　of　Al　and　Cr　within　the　oxide　layer,　and　the　oxidation　rate　of　the　coatings　is　significantly　reduced.　The　oxide　layer　of　HEA　coatings　mainly　comprises　an　inner　Al2O3　layer　and　an　outer　Cr2O3　layer.