Abstract: The nanocomposite photocatalysts, titanium oxide （TiO₂） doped by Ce⁴⁺, were prepared by impregnation method. The photocatalysts were investigated by X-ray diffraction （XRD）, transmission electron microscope （TEM） and UV-Vis transmittance spectra. The adsorbing ability of TiO₂ for Ce⁴⁺was studied by titration method. The results show that the adsorbing rate nearly reaches 100% in the range of pH=2.0-7.0. It is found that the presence of the Ce⁴⁺ ions in the TiO₂ elevates the phase transforming temperature. The photocatalysts remain anatase calcined at 600℃ and 700℃,and the rutile TiO₂ and CeO₂ begin to appeare when it is calcined at 800℃. The photocatalytic activity is evaluated by photodegradation of methyl orange （MO） in solution. The results indicate that TiO₂ doped by Ce⁴⁺extend absorption edge and show much higher photocatalytic activity compared to pure TiO₂ particles.