The invention provides high-concentration anion-doped TiO2 as well as a preparation method and application thereof, and the preparation method comprises the following steps: pre-carbonizing a titanium source, introducing an oxygen vacancy defect into the pre-carbonized titanium source through a high-temperature hydrogen reduction method, doping through doping source diffusion in a protective atmosphere, washing a doped product, and carrying out drying in vacuum to obtain high-concentration anion doped TiO2, wherein the titanium source is at least one of Ti-MOF, anatase and rutile type TiO2, and the doping source is one of sublimed sulfur, elemental selenium and red phosphorus. According to the preparation method, oxygen vacancy defects are introduced through hydrogen reduction treatment, oxygen vacancies are used for assisting heteroatoms in entering titanium dioxide or Ti-MOF crystal lattices, the high-concentration anion doping level is achieved, the preparation method has the advantages of being short in process, easy to operate, rapid and efficient, and industrial production is facilitated.