Abstract: The catalytic combustion of methane in a micro-channel whose surface was coated with platinum catalyst was studied by numerical simulation.The effects of gas phase reaction on the whole catalytic combustion process were analyzed at a high inlet pressure.A sensitivity analysis of the surface reactions mechanisms of methane combustion on platinum catalyst revealed that the most sensitive reactions affecting the heterogeneous ignition were oxygen adsorption/desorption and methane adsorption, and the most sensitive reactions affecting the gas ignition were OH· and H₂O adsorption/desorption.The combustion process of the homogeneous charge compression ignition (HCCI) engine with Pt-coated piston face was simulated.The effects of catalysis and the most sensitive reactions on the ignition timing and the concentration of intermediate species during the HCCI engine combustion were discussed.The results showed that catalytic combustion could advance the ignition timing, and the most sensitive reactions affecting the ignition timing of the HCCI engine were OH·and H₂O adsorption/desorption.