Abstract: The ordered mesoporous powders of TiO₂ with tet ragonal st ructure were prepared by an organic surfaceactive agent, solvent thermal synthesis and supercritical flux drying techniques, then the CeO₂ was stuffed into themesopores of TiO₂ powders by an int rusive precipitation method. The ordered mesoporous st ructure of CeO₂ / TiO₂composites was characterized by use of TEM, HREM, BET, etc. The formation mechanisms of the mesoporousst ructure of TiO₂ and the st ructure of nano-CeO₂ atomic group were investigated. The result s show that the CeO₂ /TiO₂ system has achieved the homogeneous composite st ructure in nano-size.