Ce-MCM-41 mesoporous molecular sieve with different silicon to cerium ratio(Si/Ce) was synthesized by hydrothermal method. and then the cerium oxide was obtained through disso lving the MCM-41 template with NaOH solution. Structure characterization by X-ray diffraction, transmission electron microscopy(TEM), Scanning electron microscopy (SEM) and N2 adsorption –desorption. The results indicated that when n（ Si/Ce）=1.0:1.0, The nano fibers diameter 4nm, Fiber length of about 500 nm, with a high surface area of 528.0 m2.g-1 , We demonstrated the high catalytic efficiency of CeO2 nanofibers as catalyst in the oxidation of methyl violet dye with H2O2 . The decoloration rate of 40 mg /L methyl violet solution reached 80.0 % with in 45min .