We　demonstrate　a　carefully　tailored　elemental　red　phosphorus　(red　P)　for　a　record-high　photocatalytic　hydrogen　evolution　rate　of　1280　mu　mol　g(-1　)h(-1).　This　performance　has　even　surpassed　some　of　the　established　compound　photocatalysts.　Systematic　studies　reveal　that　the　bismuth-catalyzed　selective　growth　of　the　preferential　crystal　phases　of　red　P　leads　to　the　formation　of　fibrous　and　Hittorf＇s　phases　at　distinctive　sites　within　the　same　pho-tocatalyst　particle　of　dendritic　morphology:　nanobranches　of　fibrous　phase　and　main　stems　of　Hittorf＇s　phase.　As　each　crystal　phase　possesses　unique　band　energy　potential,　the　intimate　heterojunction　between　the　two　phases　affords　an　effective　built-in　driving　force　for　the　efficient　transportation　of　photoexcited　charge　carriers　with　suppressed　charge　trapping　and　recombination.　The　strategy　in　crystal　phase　engineering　of　red　P　as　well　as　the　understanding　of　its　charge　transportation　properties　in　this　work　provides　new　insights　into　developing　favorable　elemental　P-based　materials　for　various　photocatalytic　applications.