The TiO2 particles were synthesized in the solvothermal method, and they were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis and differential thermal analysis (TG-DTA) and the N2 adsorption–desorption measurement. The photocatalytic property of as-prepared TiO2 particles was evaluated by the degradation experiment of methyl orange aqueous solution. Results indicated that TiO2 nanoparticles were the combination of anatase-TiO2 and rutile-TiO2 crystals with integrated crystals form and high crystallinity, which may be helpful for stabilizing the anatase and improving the photocatalytic activity. The adsorption-desorption isotherms was the typical type IV isotherm with a clear H2-type hysteresis loops in the desorption branch. The results showed mesoporous TiO2 particles had the average pore diameter of 3.587 nm, the average specific surface areas of 270.342 m2/g, and the average pore volume of 0.259 cm3/g. Meantime, the as-prepared TiO2 particles had good thermal stability and high photocatalytic activity, when being irradiated for 120 min, the degradation rate of the methyl orange aqueous solution could be up to 98.27%.