MSU-x　mesoporous　molecular　sieve　that　provided　with　high　surface　area,　adjustable　uniform　pore　diameter　and　3D　wormlike　channels　is　an　important　family　of　mesoporous　materials　developed　in　resent　years.　The　chromium　oxide　supported　MSU-x　catalytic　was　prepared　by　impregnation　of　MSU-x　in　desired　amount　of　chromium　nitrate　aqueous　solution.　The　dehydrogenation　of　isobutane　to　isobutene　under　CO2　over　the　Cr/MSU-x　catalyst　was　investigated.　The　results　indicated　that　the　decrease　of　Cr2O3　loading　up　to　12wt%　was　favorable　for　improving　activity　and　selectivity.　With　the　increasing　of　CO2/i-C4H10　ratio　in　feed　or　decreasing　of　space　velocity,　the　isobutane　conversion　could　be　improved　but　selectivity　to　isobutene　deteriorated.　The　CO2　exert　a　promotional　effect　on　reaction　conversion　by　comparison　with　the　results　in　the　absence　of　CO2.　The　24.8　of　isobutane　conversion　with　93.8%　of　isobutene　selectivity　was　obtained　over　12　wt%　Cr/MSU-x　catalyst　at　500　°C　and　atmospheric.