It is well known that SCR method is very effective for NOx removal of emissions. In order to develop a SCR catalyst system using methanol as a reductant, NO decomposition and methanol oxidation were studied over highly dispersed supported gold catalysts, and discussed on the role of gold particles. The gold catalyst was mainly prepared by deposition and wash-coating. Highly dispersed supported gold catalysts gave much higher NO conversion and selectivity to N2 than Pt/Al2O3. In methanol Oxidation, the ultra-fine gold particle increased methanol conversion, and greatly reduced byproduct such as CH3OCH3, HCHO, and CO. It was considered that the gold particle may be an effective constituent for NOx reduction by methanol.