Graphitic　carbon　nitride　(g-C3N4)　has　been　demonstrated　as　a　promising　non-metal　material　for　photocatalytic　hydrogen　evolution　(PHE),　while　its　photocatalytic　activity　is　greatly　limited　due　to　the　narrow　visible　light　response-ability　and　the　intrinsic　severe　charge　deep　trapping　and　recombination　effects.　Herein,　a　co-functionalized　g-C3N4　system　by　Se　doping　and　nitrogen　vacancies　modification　is　developed　through　a　Se　vapor-assisted-chemical　vapor　deposition　synthetic　strategy.　Advanced　characterization　results　revealed　that　Se　dopants　promote　the　visible-light　absorption　ability　of　g-C3N4,　while　nitrogen　defects-induced　shallow　trap　states　are　constructive　to　improving　charge　separation/transportation　efficiency　by　effectively　retarding　the　detrimental　charge　deep　trapping　and　recombination.　As　a　result,　the　synergistic　effect　of　the　Se　dopants　and　nitrogen　defects　leads　to　a　highly　efficient　PHE　performance　of　g-C3N4.　The　integrated　engineering　strategy　and　mechanism　understanding　provided　in　this　work　may　offer　new　insights　into　developing　other　novel　photocatalysts　for　various　applications.　©　2023　Hydrogen　Energy　Publications　LLC