Ultra-fine particles of La1−xAxMnO3 (A=Ba2+, Sr2+ or Ca2+, x≤0.3) with high surface area and single perovskite structure were prepared by a Na2CO3-NaOH coprecipitation method. The so-prepared ultra-fine particles exhibited high catalytic activity for CH4 total oxidation. The ultra-fine particles of La1−xBaxMnO3 prepared with this method were thermally more stable than LaMnO3 and La1-xSrxMnO3, and its surface areas were close to 20m2/g after sintering at 1000℃for 2 h. La1-xBaxMnO3 exhibited higher activity for methane total oxidation than La1-xSrxMnO3, and among the La1-xBaxMnO3 series La0.8Ba0.2MnO3 showed highest activity.