Green　hydrogen　is　currently　the　dominant　trend　in　the　evolution　of　hydrogen　energy,　producing　almost　no　greenhouse　gas　emissions.　Alkaline　water　electrolysis　(AWE)　is　recognized　as　a　leading　and　well-established　technology　for　producing　green　hydrogen.　However,　safety　hazards　may　occur　during　hydrogen　production　currently　as　defective　commercial　separate　membranes　used　in　the　AWE　process.　Therefore,　it　is　imperative　to　create　a　membrane　characterized　by　low　area　resistance,　high　stability,　and　high　bubble　point　pressure　(BPP)　to　realize　high-performance　AWE.　Herein,　we　synthesize　alumina-based　composite　membranes　with　Y2O3-added　and　polyethylene　glycol　coupling　agent　functionalized　Al2O3　for　AWE　through　a　phase　inversion　method.　The　porous　composite　membrane　exhibits　excellent　hydrophilicity,　with　a　lower　contact　angle　of　approximately　55　degrees.　It　also　presents　exceptional　performance　metrics,　including　a　low　area　resistance　of　about　0.17　Omega　cm(2),　an　ultrahigh　BBP　of　approximately　4.4　bar,　and　excellent　mechanical　properties　with　a　tensile　strength　of　around　25　MPa.　The　membranes　achieved　a　current　density　of　up　to　2.5　A　cm(-2)　under　2.0　V　voltage　in　a　30　wt%　KOH　solution　at　80　degrees　C　by　utilizing　commercial　catalysts.　Notably,　the　composite　membranes　exhibited　remarkable　stability,　maintaining　operation　for　over　1200　h　at　a　2.0　A　cm(-2)　current　density　without　any　performance　degradation　at　80　degrees　C.　Furthermore,　this　composite　membrane　possesses　outstanding　gas-barrier　capability　with　H-2　and　O-2　purity　higher　than　98.70　%　and　99.69　%,　respectively.　The　above　results　demonstrate　that　the　prepared　novel　high-performance　alumina-based　composite　membrane　for　hydrogen　generation　has　significant　potential　for　applications　within　the　AWE　process.