Highly ordered mesoporous TiO2 was synthesized by a hydrolysis condensation process using block copolymer P123 as the template and tetrabutyl orthotitanate (TBOT) as titanium precursor.The influences of the synthesis parameters including the volume of solvent, the ratio of the template to TBOT and reaction pH on the structure were investigated. The structure properties of the products were characterized with low-angle XRD, FT-IR, N2 adsorption-desorption analysis. The results showed that the amount of solvent played a decisive role for the formation of ordered pore structure. The proper hydrolysis pH is in neutral and acidic range. The template can be removed totally by Soxhlet extraction with ethanol and the mesoporous structure can be retained perfectly by this template removal method. The product has the BET surface area of 266.5m2/g and a narrow pore distribution with a peak at 4.34 nm.