Amorphous　Al2O3　coating　was　prepared　on　Ni-based　single　crystal　superalloy　via　atomic　layer　deposition　(ALD)　for　high　temperature　oxidation　protection.　The　oxygen　inward　transport　and　outward-cation　diffusion　were　hindered　by　amorphous　Al2O3　coating,　and　the　coated　alloy　showed　high　oxidation　resistance.　The　low　oxygen　partial　pressure　at　the　alloy/coating　interface　altered　the　alloy　oxidation　behavior,　allowing　the　priority　oxidation　of　protective　Al　and　Cr　elements.　The　oxidation　process　was　controlled　by　the　growth　of　Cr2O3　and　Al2O3.　The　coating　exhibited　high　spallation　resistance.　Degradation　of　the　coating,　the　formation　of　NiAl2O4　phase　in　amorphous　Al2O3　layer,　was　observed.