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MnxCe1-xO2 (x:0.3-0.9) prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde (HCHO).At x =0.3 and 0.5,most of the manganese was incorporated in the fluorite structure of CeO2 to form a solid solution.The catalytic activity was best at x =0.5,at which the temperature of 100％ removal rate is the lowest (270℃).The temperature for 100％ removal of HCHO oxidation is reduced by approximately 40℃ by loading 5 wt.％ CuOx into Mn0.5Ce0.5O2.With ozone catalytic oxidation,HCHO (61 ppm) in gas stream was completely oxidized by adding 506 ppm O3 over Mn0.5Ce0.5O2 catalyst with a GHSV (gas hourly space velocity) of 10,000 hr-1 at 25℃.The effect of the molar ratio of O3 to HCHO was also investigated.As O3/HCHO ratio was increased from 3 to 8,the removal efficiency of HCHO was increased from 83.3％ to 100％.With O3/HCHO ratio of 8,the mineralization efficiency of HCHO to CO2 was 86.1％.At 25℃,the p-type oxide semiconductor (Mn0.5Ce0.5O2) exhibited an excellent ozone decomposition efficiency of 99.2％,which significantly exceeded that of n-type oxide semiconductors such as TiO2,which had a low ozone decomposition efficiency (9.81％).At a GHSV of 10,000 hr-1,[O3]/[HCHO] =3 and temperature of 25℃,a high HCHO removal efficiency (≥81.2％) was maintained throughout the durability test of 80 hr,indicating the long-term stability of the catalyst for HCHO removal.