As　a　prospective　visible-light-responsive　photochemical　material,graphitic　carbon　nitride　(g-C3N4)　has　become　a　burgeoning　research　hot　topics　and　aroused　a　wide　interest　as　a　metal-free　semiconductor　in　the　area　of　energy　utilization　and　conversion,environmental　protection　due　to　its　unique　properties,such　as　facile　synthesis,high　physicochemical　stability,excellent　electronic　band　structure,and　sustainability.However,the　shortcomings　of　high　recombination　rate　of　charge　carriers,relatively　low　electrical　conductivity　and　visible　light　absorption　impede　its　practical　application.Various　strategies,such　as　surface　photosensitization,heteroatom　deposition,semiconductor　hybridization,etc.,have　been　applied　to　overcome　the　barriers.Among　all　the　strategies,functional　nanocarbon　materials　with　various　dimensions　(0D～3D)　attract　much　attention　as　modifiers　of　g-C3N4　due　to　their　unique　electronic　properties,optical　properties,and　easy　functionalization.More　importantly,the　properties　of　these　functional　nanocarbon　materials　can　be　tuned　by　various　dimensions　and　thus　there　will　be　a　way　to　overcome　the　defects　of　g-C3N4　by　choosing　different　dimensional　carbon　materials.Distinguishing　from　some　present　reviews,this　review　starts　with　the　fundamental　physicochemical　characteristics　of　g-C3N4　materials,followed　by　analyzing　the　advantages　of　functional　nanocarbon　materials　modifying　g-C3N4.Then,we　present　a　systematic　introduction　to　various　dimensional　carbon　materials.The　design　philosophy　of　carbon/g-C3N4　composites　and　the　advanced　studies　are　exemplified　in　detail.Finally,a　nichetargeting　summary　and　outlook　on　the　major　challenges,opportunities　for　future　research　in　high-powered　carbon/g-CaN4　composites　was　proposed.