NOVELTY - Preparation of mesoporous titanium dioxide involves adding poly(ethylene glycol)-embedded-poly(propylene glycol)-embedded-poly (ethylene glycol) to water, sequentially adding ammonium fluoride and concentrated hydrochloric acid, stirring, obtaining template solution, adding tetraethyl orthosilicate and titanium isopropoxide, stirring, vacuum-drying, adding mixture of concentrated sulfuric acid and hydrogen peroxide to the resultant product, oxidizing, filtering, adding 0.2-40% hydrogen fluoride solution, washing, and drying.    USE - Preparation of mesoporous titanium dioxide used in preparation of perovskite organic solar cell (claimed).    ADVANTAGE - The method enables preparation of mesoporous titanium dioxide having high specific surface area, and narrow pore size distribution. The perovskite organic solar cell using the mesoporous titanium dioxide has open circuit voltage of 0.94 V or less and cell efficiency of 10.48% or less.    DETAILED DESCRIPTION - Preparation of mesoporous titanium dioxide involves adding poly(ethylene glycol)-embedded-poly(propylene glycol)-embedded-poly (ethylene glycol) to water, sequentially adding ammonium fluoride and concentrated hydrochloric acid, stirring at 10-40 degrees C and 500 rpm for 30-45 minutes, obtaining template solution, adding tetraethyl orthosilicate and titanium isopropoxide, stirring at 10-40 degrees C and 500 rpm for 20-26 minutes, transferring resultant product to reactor, heating at 5 MPa and 100-125 degrees C for 15-18 hours, vacuum-filtering with filter having pore diameter of 1 mu m, vacuum-drying at 60 degrees C for 2-3 hours, adding mixture of 16 mol/L concentrated sulfuric acid and 10 weight/weight% hydrogen peroxide to the resultant product, oxidizing at 110-120 degrees C and 5 MPa for 10-15 hours, filtering, adding 0.2-40% hydrogen fluoride solution, reacting for 11 hours, washing with deionized water, drying at 60 degrees C, and obtaining mesoporous titanium dioxide having specific surface area of 220-88 cm2/g and average pore size of 8-18 nm. The mass ratio of poly(ethylene glycol)-embedded-poly(propylene glycol)-embedded-poly (ethylene glycol) and ammonium fluoride is 1:(0.03-0.01). The added amount of concentrated sulfuric acid is 10-18 vol.%. The mass ratio of tetra-ethyl orthosilicate and titanium isopropoxide is (0.1-2):1.