A core-shell structured Cu/SiO2 catalyst with a copper particle size of 4-7 nm and a SiO2 shell of 1 nm was developed. The catalyst was highly active and stable for methyl acetate hydrogenation to ethanol. The copper particles were not enlarged during 96 h reaction at 523 K. The Cu+/(Cu0+Cu+) ratio increased during the reaction due to the competitive adsorption of methyl acetate and hydrogen. A proper Cu+/(Cu0+Cu+) ratio is the prerequisite for achieving a durable catalyst with higher catalytic performance.