Searching　for　highly　efficient　photocatalysts　for　water　oxidation　is　the　footstone　for　the　development　of　overall　water　splitting　systems　and　has　been　actively　pursued.　The　construction　of　artificial　Z-scheme　heterojunction　photocatalysts　has　been　conclusively　proven　to　be　effective　in　boosting　charge　transport　property　and　in　improving　the　OER　performance.　Herein,　Ag3PO4　particles　anchored　on　modified　crispy　g-C3N4　flakes　have　been　successfully　fabricated.　KOH-assisted　surface　modification　of　g-C3N4　flakes　and　intimate　interfacial　contact　favor　the　accelerated　charge　transfer　and　highly　improved　OER　efficiency.　Ultrafast　spectroscopy　results　reveal　that　modified　g-C3N4　with　crispy　nanostructures　possesses　more　trap-induced　long-lived　photogenerated　holes,　which　are　extremely　helpful　to　combine　with　photo-generated　electrons　from　the　conduction　band　(CB)　position　of　Ag(3)PO(4　)via　the　specific　Z-scheme　configuration,　leaving　more　holes　in　the　valence　band　(VB)　of　Ag3PO4　for　the　enhanced　OER.　Superb　oxygen-evolving　performance　highlight　the　great　promise　of　Z-scheme　Ag3PO4　-based　heterojunctions　in　solar-driven　photocatalytic　water　splitting.