Abstract: Cluster-like CeO2 nanopowders were prepared by hydrothermal method in mixed alcohol-water solvents with Ce(NO3)3·6H2O and C2H2O4·2H2O as raw materials and triblock copolymers P123 as template. The effects of hydrothermal reaction temperature, ratio of cerium nitrate to oxalic acid (nCH), pH of solution and reaction time on CeO2 powders were studied to obtain the optimum synthesis parameters for synthesizing cluster-like CeO2 nano-powders. The catalytic degradation experiment of CeO2 prepared by the optimum parameters was carried out in acid fuchsin solution, and the degradation results were compared with the results of bulk CeO2. The results show that the optimum parameters for synthesizing cluster-like nano-powders can be summarized as follows: hydrothermal reaction temperature of 200 ℃, nCH of 2∶3, solution pH of 1 and reaction time of 360 min. Compared with bulk CeO2, the catalytic performance in scid fuchsin solution for the cluster-like CeO2 prepared using these optimum parameters increased greatly.