Atomically　precise　metal　nanoclusters　(NCs)　have　emerged　as　a　pivotal　sector　of　metal　nanomaterials　due　to　their　unique　atomic　stacking　mode,　quantum　confinement　effect　and　abundant　active　sites.　In　particular,　the　discrete　energy　band　structure　of　metal　NCs　renders　them　emerging　photosensitizers.　Nonetheless,　atomically　precise　metal　NCs　suffer　from　ultrashort　charge　lifetime　and　poor　stability,　impeding　the　construction　of　robust　and　stable　metal　NC-based　photosystems.　Herein,　we　designed　multilayered　metal　oxide　(MO)/(metal　NCs/insulating　polymer)(n)　(metal　NCs:　Au-x@GSH,　Ag-x@GSH,　and　Au-25@GSH(18)　NCs)　heterostructured　photoanodes,　wherein　glutathione　(GSH)-capped　metal　NCs　and　an　ultra-thin　non-conjugated　insulating　poly(allylamine　hydrochloride)　(PAH)　layer　are　electrostatically　layer-by-layer　self-assembled　on　MO　substrates　in　a　periodic　face-to-face　stacking　mode.　We　infer　that　electrons　photoexcited　over　metal　NCs　in　MOs/(metal　NCs/PAH)(n)　photosystems　can　be　effectively　extracted　and　tunneled　to　the　adjoining　MO　substrates　through　the　insulating　polymer　interim　layer　by　engendering　the　tandem　charge　transfer　pathway,　thus　significantly　boosting　the　visible-light-driven　photoelectrochemical　water　oxidation.　This　work　opens　up　a　new　frontier　for　strategically　mediating　tunable　charge　transport　over　atomically　precise　metal　NCs　towards　solar-to-hydrogen　conversion.