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.(c)　2023　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.