A　series　of　gamma-graphyne/TiO2　nanotube　array　heterostructures　are　first　synthesized　by　a　facile　and　environmental-friendly　drop-coating　method.　The　prepared　heterostructures　is　completely　investigated　by　a　collection　of　characterizations.　Interestingly,　the　unique　C-O-Ti　linkage　between　gamma-graphyne　and　TiO2　nanotube　arrays　is　verified　by　both　X-ray　photoelectron　spectroscopy　and　Fourier　transform　infrared　analysis.　After　modification　of　gamma-graphyne,　the　maximum　transient　photo-current　and　photo-potential　of　TiO2　nanotube　arrays　are　improved　by　2.2　and　1.3　folds,　respectively.　Moreover,　a　maximum　of　3.64　and　1.35　folds　enhancements　are　severally　verified　for　the　photoelectrocatalytic　degradation　of　levofloxacin　and　rhodamine　B　over　the　heterostructures　compared　to　that　of　TiO2　nanotube　arrays.　Furtherly,　the　heterostructures　also　show　superior　photoelectrocatalytic　performance　on　nitrogen　fixation　and　oxygen　evolution　than　TiO2　nanotube　arrays.　The　crystal,　morphological,　photoelectrochemical,　and　photoelectrocatalytic　stability　of　the　heterostructures　are　confirmed.　This　work　sheds　light　on　designing　gamma-graphyne　modified　composites　for　photoelectrochemical　and　photoelectrocatalytic　application.