The mesoporous TiO_2 thin film was synthesized by spin-coating method from C_16EO_20 as a struchure-directing agent. The mesophase was strongly affected by the solvent evaporation period, exhibiting the best stuctural integrity after 3 dauys of aging at 40℃ in open beaker. The XRD pattem and TEM image showed that a well-ordered cylindrical pore structures were formed, which can be indexed in a 2D hexagonal(ρσm) or 2D centered-rectangular cell(c2m) in the direction normal to surface. The UV/Vis. absorbance of mesostructured TiO_2 film was larger in short wavelength below 300nm than that of amorphous film Moreover the photocurent response of mesostructured TiO_2 film was larger than amorphous film which indicates that high surface area,structural regularity of mesophase, which the distinct order on mesoscopis scale(long range) of titania is affect somewhat to the photoelcctronic property as well as order on the atomic sccalc(short range).