NOVELTY - Preparing titanium dioxide thin film comprises: (i) cleaning and drying the substrate; (ii) shielding the substrate, using metallic zinc, filling working gas, controlling the pressure to grow single-element zinc thin film on the substrate, removing the sieve screen, using metallic titanium, filling reacting gas and controlling to sputter and grow titanium oxide thin film on the single-element zinc thin film, and repeating several times to obtain laminated composite film of single-element zinc and titanium oxide; and (iii) soaking the laminated composite film in acid and drying.    USE - The titanium dioxide thin film is useful e.g. in solar cells, biological field, optical catalysis.    ADVANTAGE - The prepared titanium dioxide has controllable preparation process, large specific surface area, uniform distribution, adjustable thickness and high adhesion. The method: easily controls the quality of the product in large-scale industrial production; reduces overall production costs; and controls oxidation-reduction performance of the material to some extent.    DETAILED DESCRIPTION - Preparing titanium dioxide thin film with high specific surface area comprises: (i) cleaning the substrate sequentially by an organic solvent and deionized water under ultrasonic condition and drying the substrate; (ii) shielding the substrate by sieve screen, storing in sputtering reacting chamber, vacuumizing and heating, taking metallic zinc as a target material, filling working gas, controlling the pressure as 0.5-2 Pa to grow single-element zinc thin film on the substrate, removing the sieve screen, using metallic titanium as a target material, filling reacting gas and controlling the pressure as 0.5-2 Pa to sputter and grow titanium oxide thin film on the single-element zinc thin film, and repeating several times to obtain laminated composite film of single-element zinc and titanium oxide; and (iii) soaking the laminated composite film in 1x 10-6 to 1x 10-1 mol/l of acid and drying to obtain the titanium dioxide thin film with high specific surface area.