CexMn1-xO2 series catalysts were prepared with the sol-gel method. The catalytic activity for soot oxidation was investigated by thermogravimetric analysis(TGA). All catalysts were elevated by X-ray diffraction (XRD), nitrogen adsorption techniques, temperature programmed desorption (TPD), Raman spectroscopy, temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The influence of the catalysts on soot oxidation characteristics and the relationship between the catalytic oxygen species and the combustion of soot were mainly discussed. The results revealed that the crystal structure of the catalyst did not change after Mn doped CeO2. Mn inhibited the growth of CeO2 cell and promoted the formation of oxygen vacancies on the catalyst surface, which was conducive to the activation and migration of oxygen species. Ce0.5Mn0.5O2 had the most absorptive atomic oxygen O-, and the ignition temperature and peak temperature of Ce0.5Mn0.5O2 were decreased by 37 and 50 degrees C compared to CeO2, respectively.