MnO2　with　nanocubes　and　nanorods　were　synthesized　by　a　hydrothermal　process,　and　their　structures　and　catalytic　performances　in　methane　combustion　were　investigated.　The　activity　results　show　that　methane　conversion　over　nanocubic　MnO2　is　more　than　90%　at　350　degrees　C,　which　is　much　higher　than　that　of　MnO2　nanorods.　N-2　physisorption,　XPS　and　H-2-TPR　results　demonstrate　that　the　superior　catalytic　performance　of　nanocubic　MnO2　is　associated　with　its　higher　BET　surface　area,　smaller　crystalline　size,　more　surface　oxygen　vacancies　and　better　low-temperature　reducibility.　In　situ　DRFIFTS　results　demonstrate　that　the　carboxylates　species　are　the　main　intermediate　species　in　methane　oxidation.