Exploring　active　catalyst　materials　for　solar-driven　photocatalytic　water　splitting　into　oxygen　has　proven　extremely　challenging,　mostly　due　to　poor　oxygen-evolving　efficiency　originating　from　intrinsically　sluggish　oxygen　evolution　reaction　(OER)　kinetics.　Ag3PO4　has　been　actively　pursued　as　a　promising　photocatalyst　for　oxygen　evolution　from　water-splitting.　However,　its　low　OER　efficiency　is　a　long　standing　problem.　Both　the　construction　of　Z-scheme　Ag3PO4-based　composite　photocatalytic　systems　and　the　optimization　of　surface　morphology　and　interfacial　contact　in　heterojunctions　photocatalysts　would　be　beneficial　for　boosting　OER　efficiency.　Here　we　report　on　the　fabrication　of　Ag3PO4/fish　scale-like　graphitic　carbon　nitride　(g-C3N4)　sheet　composites　with　well-defined　heterostructures　and　intimate　interfacial　contact　driven　by　electrostatic　assembly.　The　Ag3PO4/modified　g-C3N4　composites　photocatalyst　reveals　significantly　enhanced　oxygen-evolving　activity　under　light-emitting　diode　(LED)　illumination.　Effective　surface　modification　of　g-C3N4,　strong　interfacial　interactions　between　two　semiconductors　and　tandem　Z-scheme-type　pathway　for　more　efficient　charge　transfer　synergistically　accelerates　the　redox　capability　of　Ag3PO4　for　OER.　This　work　may　provide　new　insights　into　the　design　and　construction　of　high-performance　solar-driven　Z-scheme　photocatalytic　water　splitting　systems.