An effective manganese oxide (MnO2) was synthesized by a combined ball-milling and selective atom removal method from LaMnO3. The catalyst showed a high activity for methane catalytic combustion with 50% CH4 conversion temperature of 385 degrees C at space velocity of 21,000 mL/g/h, higher than the MnO2 catalyst prepared by traditional method. The physicochemical properties were characterized by XRD, SEM, TEM, N-2 adsorption-desorption, H-2-TPR, and XPS. The results confirmed that the high performance is due to the higher specific surface area and structural defects. This study will offer a facial strategy to synthesize a highly defective MnO2 catalyst for the application in methane combustion and beyond.