A novel, simple, and general method for preparing a highly dispersed supported metal catalyst was developed by modification of a silica surface with ethylene glycol (EG) before the impregnation of cobalt precursors. The modified surface of the silica support significantly improved the dispersion of supported cobalt oxide and formed more Co3+ species on the surface of Co3O4 particles, resulting in very high catalytic activity in CO oxidation. The obtained catalysts were characterized by XRD, TEM, and XPS.