The　enhancement　of　photogenerated　carrier　separation　efficiency　is　a　significant　factor　in　the　improvement　of　photocatalyst　performance　in　photocatalytic　hydrogen　evolution.　Heteroatom　doping　and　defect　construction　have　been　considered　valid　methods　to　boost　the　photocatalytic　activity　of　graphitic　carbon　nitride.　Herein,　we　report　graphitic　carbon　nitride　modified　with　P　doping　and　N　defects　(PCNx),　and　the　effects　of　doping　and　defects　were　investigated　in　photocatalytic　H2　evolution.　Its　hydrogen　evolution　rate　can　reach　up　to　about　59.1　μmol　h−1,　which　is　more　than　123.1　times　higher　than　pristine　graphitic　carbon　nitride　under　visible　light　irradiation.　Importantly,　the　apparent　quantum　efficiency　reaches　8.73%　at　420　nm.　The　excellent　performance　of　the　PCNx　photocatalyst　was　attributed　to　the　following　aspects:　(I)　the　large　BET　surface　area　of　PCNx　affords　more　active　sites　for　H2　production　and　(II)　the　introduction　of　P　and　N　defects　can　accelerate　the　charge　carrier　separation　and　transfer　efficiency,　leading　to　more　efficient　photocatalytic　hydrogen　production.　The　photocatalyst　showed　obviously　enhanced　activities.　©　2023　The　Royal　Society　of　Chemistry.