The invention discloses a titanium dioxide-based catalyst, and a preparation method and application thereof. The preparation method comprises the following steps: mixing titanyl sulfate, niobium pentachloride, urea, sodium dodecyl benzene sulfonate and water, then carrying out a reaction, carrying out cooling after the reaction, and subjecting a precipitate to centrifugation, washing, drying and calcinations so as to obtain a titanium niobium binary oxide carrier; and mixing the titanium niobium binary oxide carrier with an aqueous copper nitrate solution and then carrying out ultrasonic treatment, stirring, drying and calcining successively so as to obtain the titanium dioxide-based catalyst. The preparation method provided by the invention is simple in process and easy to operate and implement. The titanium dioxide-based catalyst prepared in the invention can be used for selective catalytic reduction of nitrogen oxides in virtue of ammonia, has high nitrogen oxide reduction ability and nitrogen selectivity, a wide reaction window, high anti-sulfur dioxide poisoning performance and high hydrothermal stability, and also has the advantages of economic performance, environment friendliness, easiness in industrialization, etc.