Graphene　promoted　triphasic　N/Ti3+-TiO2　(GNTT)　heterostructures　with　different　weight　addition　ratios　of　graphene　have　been　assembled　by　a　facile　in-situ　hydrothermal　treatment　of　TiN　and　graphene　oxide.　The　obtained　GNTT　photocatalysts　are　characterized　by　a　collection　of　techniques　such　as　X-ray　diffraction　(XRD),　field　emission　scanning　electron　microscopy　(FE-SEM),　high　resolution　transmission　electron　microscopy　(HR-TEM),　X-ray　photoelectron　spectroscopy　(XPS),　UV–visible　spectroscopy,　and　photoluminescence　(PL),　etc.　It　is　demonstrated　that　graphene　modified　N/Ti3+　codoped　TiO2　with　ternary　phases　mixture　of　brookite,　anatase　and　rutile　can　be　obtained.　Furthermore,　the　GNTT　heterostructure　photocatalysts　exhibit　an　enhanced　photoactivity　for　photocatalytic　degradation　of　methyl　blue,　levofloxacin,　and　rhodamine　B　as　compared　with　TiO2,　N-doped　TiO2,　and　N/Ti3+　codoped　TiO2　(NTT).　The　reason　for　the　improved　photoactivity　can　be　listed　as　follows:　i)　N　and　Ti3+　doping　can　severally　form　N2p　impurity　level　above　valance　band　(VB)　and　local　states　below　the　conduction　band　(CB)　of　TiO2,　which　contribute　to　the　visible　light　response　of　TiO2;　ii)　the　ternary　heterophase　junction　can　efficiently　transfer　and　separate　photogenerated　electron-hole　pairs;　iii)　graphene　acts　as　an　electron　reservoir　to　trap　and　transport　the　electrons　photogenerated　from　TiO2.　The　synergistic　effect　of　these　factors　accounts　for　the　photoactivity　advancement　of　GNTT　photocatalysts.　This　study　develops　a　novel　approach　to　improve　the　visible　light　utilization　of　TiO2　and　facilitates　their　applications　in　the　environment　and　energy　issues.　©　2019　Elsevier　B.V.