High-entropy　alloys　Al0.5　FeCoCrNi,　Al0.5　CoCrFeNiSi0.2　and　Al0.5　FeCoCrNiTi0.5　were　prepared　by　the　arc　melting　and　casting　method　(subscript　indicats　molar　ratio).　The　oxidation　resistance　of　the　three　high-entropy　alloys　at　900　°C　were　studied.　The　morphology　composition　and　structures　of　the　oxide　scales　on　alloys　were　characterized　by　scanning　electron　microscopy　(SEM)　attached　with　energy　dispersive　X-ray　spectrometer　(EDS)　and　X-ray　diffraction　(XRD).　The　results　show　that　three　kinds　of　high-entropy　alloys　all　belong　to　the　oxidation　resistant　grade.　The　oxidation　mass　gain　curves　of　Al0.5　FeCoCrNi　and　Al0.5　FeCoCrNiSi0.2　are　similar,　the　velocity　of　the　oxidation　mass　gains　of　Al0.5　FeCoCrNiTi0.5　is　faster.　The　oxides　of　Al0.5　FeCoCrNi　and　Al0.5　FeCoCrNiSi0.2　Cr2O3　with　a　small　amount　of　AIN　particles　inside;　the　oxides　of　high-entropy　alloy　Al0.5　FeCoCrNiTi0.5　are　complex,　there　covered　CoFe2O4　spinel　and　mixed　oxides　with　a　small　amount　of　nitrideinside.