TiO2　has　been　widely　employed　as　a　photocatalyst　for　water　splitting　owing　to　its　high　activity,　low　cost,　abundance,　safety,　and　stability.　However,　the　further　utilization　of　TiO2　is　still　confined　to　the　wide　band　gap　and　the　rapid　recombination　speed.　Carbon　has　metallic　conductivity　and　a　large　electron　storage　capacity,　which　can　help　to　absorb　photoexcited　electrons　and　enhance　charge　separation　and　transfer.　Herein,　we　fabricated　the　ultra-thin　carbon-doped　TiO2　nanotube　arrays　(TNTAs).　The　as-prepared　UTC-doped　TiO2@TNT　exhibited　high　photoelectrochemical　(PEC)　activity,　realizing　a　high　H2　evolution　rate　up　to　41.3　mu　mol　cm-2　h-1　(AM　1.5G)　and　1.3　mu　mol　cm-2　h-1　(visible　light),　which　exhibit　significantly　narrowed　band　gaps　and　decreased　charge　resistance.　Using　ultra-thin　carbon　doping　in　TiO2　nanotube　arrays　opens　up　a　new　avenue　for　optimizing　photocatalysts　for　PEC　water　splitting.