SIn this study, experiments have been conducted to investigate parameters that effect the catalytic reaction of methane. Parameters considered were catalysts, catalyst additives, space velocity and exhaust gas components (NO, CO, H2O, O2, CO2). Catalysts used in the experiment were Pd and Pt metal loaded on γ-Al2O3 on a cordierite monolith. Methane conversion efficiency was improved for the Pd series catalyst with additive of La and Zr. With Pd/Pt catalyst, the presence of nitric oxide and water vapor showed an inhibitory effect on methane oxidation. Methane conversion efficiency decreased rapidly over 60000 h-1 space velocity.