Employing　P123　as　a　structure　directing　agent　and　acetic　acid　as　an　interfacial　protector,　ordered　mesoporous　silicon-doped　gamma-alumina　with　high　thermal　stability　was　synthesized　through　a　modified　sol-gel　process　by　adding　aluminum　isopropoxide　in　batches　to　control　the　hydrolytic　and　condensation　rate　of　Al3+.　When　the　silicon　content　was　10-25　wt%,　the　specific　surface　area　of　the　as-obtained　samples　were　higher　than　others.　Especially　when　the　silicon　content　up　to　20　wt%,　the　sample　still　maintained　ordered　mesoporous　gamma-Al2O3　phase　with　a　large　specific　surface　area　of　139.8　m(2)　g(-1)　and　narrow　pore　size　distribution　even　the　calcination　temperature　up　to　1100　degrees　C.　Taking　as-synthesized　ordered　mesoporous　alumina　COMA)　as　carrier,　the　catalysts　with　high　thermal　stability　supported　by　Pd　were　obtained　by　a　facile　process　of　thermal　incipient　wetness　impregnation,　which　shows　highly　dispersed　nano-particles　and　ordered　mesostructure.　When　applied　the　catalysts　in　the　catalytic　converters　of　simulated　exhaust　automobile　gases,　it　was　found　that　the　ordered　mesostructure　and　high　surface　area　showed　significant　effects　in　promoting　catalytic　activity.　The　as-synthesized　ordered　mesoporous　Pd-alumina　catalyst　exhibited　an　excellent　catalytic　activity　for　gas　mixture　including　CO,　NO　and　hydrocarbon　(HC).　(C)　2016　Elsevier　B.V.　All　rights　reserved.