Abstract: The Co-modified CeO₂ composites with high active crystal planes were synthesized by simple one step hydrothermal method. The structure of Co-modified CeO₂ composites was characterized by specific surface area and porosity analyzer, TG-DSC, TEM, SEM, XRD, ultraviolet-visible spectrophotometer (UV-vis), XPS and photothermal catalytic denitration. The results show that as the amount of Co increases, the specific surface area of the Co-modified CeO₂ composites increases. The exposed high active surface is (200) and (220) crystal face, while the Co-modified CeO₂ composites mainly show rod-like structure; when the concentration of Co content precursor increases, CeO₂ has a nanorod structure, and the Co produces in the form of Co₃O₄ by chemical band connection with surface oxygen. The results of thermal-photocatalytic denitration test show that the catalytic efficiency of the Co-modified CeO₂ composites reaches 98% with 15% molar ratio of Co to Ce at 400℃ calcination temperature.