It　is　of　practical　importance　to　develop　a　stable　and　accessible　methane　combustion　catalyst　which　could　retain　an　excellent　activity　under　drastic　conditions.　Herein,　we　introduce　a　facile　approach　to　extend　the　stability　of　conventional　Pd/Al2O3　catalysts　through　tailoring　the　pore　size　of　mesoporous　aluminas　(MAs)　and　the　interaction　between　Pd　and　AI.　By　modulating　the　addition　of　templates　(deoxycholic　acid　and　polyvinylpyrrolidone),　a　series　of　MAs　with　tunable　and　uniform　pore　size　were　obtained　through　a　designed　sol-gel　method.　Unexpectedly,　Pd/MA-800-5　catalyst　prepared　with　relatively　large　pore　size　(ca.　12　nm)　MAs　exhibited　an　efficient　and　sustained　performance　under　a　variety　of　operating　conditions,　while　those　prepared　with　small　pore　size　(ca.　5-7　nm)　MAs　suffered　from　a　significant　loss　of　activity　during　high　temperature　cyclic　reactions　(280-850　degrees　C)　due　to　the　decomposition　of　confined　PdO.　The　enhancement　could　be　attributed　to　the　suitable　particle　size,　higher　crystallinity,　generated　active　sites,　improved　reducibility,　and　thermal　stability　of　PdO　species.　Moreover,　the　variation　of　pore　size　also　resulted　in　a　different　reaction　mechanism.　Such　a　pore　size　promotion　strategy　effectively　invoked　a　superior　catalytic　performance　while　keeping　the　catalyst　components　simple,　which　can　be　extended　to　prepare　other　high-performance　metal　oxide-supported　catalysts　for　catalytic　applications.