Pd/Al2O3　catalysts　modified　by　different　amount　of　magnesium　were　fabricated　for　catalytic　combustion　of　methane　(CCM).　After　the　introduction　of　different　amount　of　magnesium,　Al2O3,　MgAl2O4-like　mixed　oxide　and　Mg(Al)Ox　solid　solution　were　formed.　Owing　to　the　formation　of　distinguished　supports,　the　supported　Pd　species,　i.e.　metallic　Pd,　PdOx　and　support-Pd　oxide　complex　were　formed,　and　they　were　quite　different　in　relative　content　and　Pd↔PdO　transformation　ability.　It　was　found　that　PdOx　was　active　at　low　temperature,　while　metallic　Pd　particles　and　support-Pd　oxide　complex　were　active　at　high　reaction　temperature.　The　one　with　Mg/Al　mole　ratio　of　1:3　was　the　most　easily　in　Pd↔PdO　transformation,　demonstrating　the　best　catalytic　activity　towards　CCM　reaction.　©　2019,　Science　Press.　All　right　reserved.