This paper relates to a novel preparation method of metal supported catalysts using microemulsions. The size distribution of metal particles in the catalysts, thus, prepared was appreciably narrow and the average particle size was much smaller than that of the conventional catalyst prepared from impregnation. It was found that the particle size could be controlled by the conditions of microemulsions regardless of metal content. The Ph, Pd and Pt catalysts prepared from microemulsions were found to exhibit a much higher activity for the hydrogenation of carbon dioxide than those from impregnation.