The catalytic combustion reaction of hydrogen/air mixture was studied in a microchannel reactor. The effects of operation conditions on reactor behavior were investigated in detail by using both mathematic modeling and experiment work. Explosive mixtures of hydrogen/air ［3%(mol)—15%(mol)］ were safely handled in this reactor. The results showed that catalytic combustion reaction can be operated at high space velocity

isothermal and kinetic controlled regimes. Under the conditions of inlet hydrogen concentration of 8%(mol)，reaction temperature of 150 ℃，space velocity of 106 h-1，hydrogen conversion was still higher than 90%.