A series of V-MCM-41 were in situ synthesized. The textual properties and vanadium species were systematically characterized. The results showed that the catalysts could still maintain a mesoporous structure and high specific surface area. The vanadium species were highly dispersed on the surface, with the coexistence of polymeric vanadium species. Isobutane dehydrogenation was performed by employing CO2 as a soft oxidant. The results revealed an almost linear relationship between the activity and surface vanadium sites. Isolated vanadium species were more active for isobutane dehydrogenation. The isobutane dehydrogenation reaction in the presence of CO2 could proceed simultaneously through oxidative dehydrogenation and non-oxidative dehydrogenation followed by the reverse water gas shift reaction.