TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: Titanic acid ester is tetrabutyl titanate, tetraethyl titanate or tetraisopropyl titanate. Titanate is titanium tetrachloride. Organic acid is hydrochloric acid, sulfuric acid or nitric acid.    TECHNOLOGY FOCUS - POLYMERS - Preferred Parameters: The thickness of titanium dioxide thin film material with grading structure is 20-100 mm; the diameter of titanium dioxide nanometer bar is 100-300 nm, and the length is 1-3 mm. The diameter of titanium dioxide thread is 0.2-2 mm and diameter of titanium dioxide fiber is 2-6 mm. Preparation: Titanium dioxide thin film material is prepared by (1) confecting titanium dioxide precursors solution for electrostatic spinning; titanium dioxide precursors solution for electrostatic spinning is comprised of polyvinylpyrrolidone (PVP) with mass concentration of 0.2-2%, acetic acid with mass concentration of 10-30%, titanic acid ester or titanate with mass concentration of 10-30%, and the remaining is ethanol; (2) titanium dioxide precursors solution obtained from (1) is loaded to the liquid-feeding device of the electrostatic spinning device to enable the titanium dioxide precursors sol to be jetted from the jet device of electrostatic spinning device in the form of titanium dioxide precursors thread; and obtaining thin film comprised of titanium dioxide precursors thread on the receiving device; (3) baking the thin film comprised of titanium dioxide precursors thread obtained in (2) on the muffle furnace to obtain titanium dioxide spinning film comprised of titanium dioxide thread; (4) confecting the titanium dioxide precursors solution used in the hydro-thermal synthesis, which is comprised of titanic acid ester or titanate with mass concentration of 0.5-5%, inorganic acid with mass concentration of 5-25%, and the remaining is water; (5) loading the titanium dioxide precursors solution obtained in (4) and titanium dioxide spinning film obtained in (3) to the vessel; where the mass ratio of titanium dioxide precursors sol to the titanium dioxide spinning film is 200:1-10:1; putting the sealed vessel into the oven; heating at 50-200 degrees C and carrying out the hydro-thermal synthesis to enable the titanium dioxide nanometer bar to grow on the titanium dioxide spinning film; and obtaining the titanium dioxide thin film material with grading structure. Preferred Conditions: The baking in (3) is at 500 degrees C for 2 hours. In (5) heating at 50-200 degrees C for 2-24 hours.