Atomically　precise　metal　nanoclusters　(NCs)　have　been　deemed　as　a　new　generation　of　metal　nanomaterials　in　the　field　of　solar　energy　conversion　due　to　their　unique　atomic　stacking　manner,　quantum　confinement　effects,　light-harvesting　capability　and　multitude　of　active　sites.　Nonetheless,　wide-spread　application　of　monometallic　NCs　is　blocked　by　the　ultrashort　carrier　lifespan,　uncontrollable　charge　transport　pathway,　and　light-induced　poor　stability,　impeding　the　construction　of　robust　and　stable　metal　NC-based　photosystems.　Herein,　we　report　the　fabrication　of　stable　alloy　(Au1-x　Ptx　)　NCs　photosystem,　for　which　tailor-made　negatively　charged　L　-glutathione　(GSH)-capped　Au1-x　Ptx　NCs　as　the　building　blocks　are　controllably　deposited　on　the　BiVO4　(BVO)　by　a　self-assembly　approach　for　steering　enhanced　light　absorption　and　interfacial　charge　transfer　over　alloy　NCs-based　photoanodes　(Au1-x　Ptx　/BVO).　The　self-assembled　Au1-x　Ptx　/BVO　composite　photoanode　exhibits　the　significantly　enhanced　photoelectrochemical　water　oxidation　performances　compared　with　pristine　BVO　and　Aux　/BVO　photoanodes,　which　is　caused　by　the　Pt　atom　doping　into　the　Aux　NCs　for　elevating　photosensitivity　and　boosting　the　stability.　The　synergy　of　Au　and　Pt　atoms　in　alloy　NCs　protects　the　gold　core　from　rapid　oxidation,　improving　the　photostability　and　accelerating　the　surface　charge　transfer　kinetics.　Our　work　would　significantly　inspire　ongoing　interest　in　unlocking　the　charge　transport　characteristics　of　atomically　precise　alloy　NCs　for　solar　energy　conversion.　(c)　2024　Published　by　Elsevier　B.V.　on　behalf　of　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.