White　TiO2　nanoparticles　(NPs)　have　been　widely　used　for　cancer　photodynamic　therapy　based　on　their　ultraviolet　light-triggered　properties.　To　date,　biomedical　applications　using　white　TiO2　NPs　have　been　limited,　since　ultraviolet　light　is　a　well-known　mutagen　and　shallow　penetration.　This　work　is　the　first　report　about　hydrogenated　black　TiO2　(H-TiO2)　NPs　with　near　infrared　absorption　explored　as　photothermal　agent　for　cancer　photothermal　therapy　to　circumvent　the　obstacle　of　ultraviolet　light　excitation.　Here,　it　is　shown　that　photothermal　effect　of　H-TiO2　NPs　can　be　attributed　to　their　dramatically　enhanced　nonradiative　recombination.　After　polyethylene　glycol　(PEG)　coating,　H-TiO2-PEG　NPs　exhibit　high　photothermal　conversion　efficiency　of　40.8%,　and　stable　size　distribution　in　serum　solution.　The　toxicity　and　cancer　therapy　effect　of　H-TiO2-PEG　NPs　are　relative　systemically　evaluated　in　vitro　and　in　vivo.　The　findings　herein　demonstrate　that　infrared-irradiated　H-TiO2-PEG　NPs　exhibit　low　toxicity,　high　efficiency　as　a　photothermal　agent　for　cancer　therapy,　and　are　promising　for　further　biomedical　applications.