The meso silica supported novel nano-size gold catalysts promoted by MgO have been synthesized using deposition-precipitation technique for the total oxidation of carbon monoxide. The effects of MgO promoter and preparation procedure on the structure and performance of gold catalysts have been investigated. Better gold dispersion, smaller average size of Au particles and more oxygen mobility were observed in the Au/MgO/SiO2-SH catalyst using NaOH as precipitation agent, over which the turnover frequency (TOF) was much better than that of the sample without promotion. The temperature of the CO total conversion over the sample Au/MgO/SiO2-SH is about 250 K lower than that over the silica which directly supported gold catalyst. (C) 2011 Published by Elsevier B.V.