A teehnique for preparing perovskite-type oxides was developed. By this technique, ultra-fine particles of La0.9 RE0.1MnO3 (RE: Y, Qe, Pr, Sin, Gd, or Dy) with high surface area and single perovskite structure were prepared, and the series of La0.9 RE0.1MnO3 catalysts were studied experimentally. The so prepared ultra-fine particles exhibites high catalytic activity for CH4 total oxidation. The ultra-fine particles of La0.9 RE0.1MnO3 (except for La0.9 Pr0.1MnO3) prepared by this method are thermally much more stable than LaMnO3. of the La0.9RE0.1MnO3 series, La0.9Y0.1MnO3 is most thermally stable, and La0.9Y0.1MnO3 or La0.9Gd0.1MnO3 (varies with calcitation temperature) exhibits the highest catalytic activity for total oxidation of methane. The specific surtface area of La0.9Y0.1MnO3 calcined st 1000℃ reaches 14.9m2·g-1, while the specific suface area of LaMnO3 calcined at the same temperature is only 1.8 m2·g-1.