The Fe/SiO2 catalysts prepared using water-in-oil (w/o) microemulsions exhibited more than two-fold CO conversions as compared to the impregnated catalysts in CO hydrogenation. The catalysts produced the C2+ oxygenates with an extremely high selectivity of >40 C mol%, while the impregnated catalysts produced mainly hydrocarbons, The TPR results showed that Fe particles in the catalysts prepared using w/o microemulsion were difficult to reduce and that a considerable amount of FeO remained in the catalyst even after the reduction with H-2 at 873 K for 10h. The superior activity of the catalysts for the C2+ oxygenates synthesis was attributed to the existence of the stable Fe oxide species under the reaction condition.