Cellulosic ethanol can be produced via a chemocatalytic approach in which cellulose is first converted into methyl glycolate (MG) in methanol with the promotion of W-based catalyst and oxygen atmosphere, and the formed MG was then hydrogenated to ethanol over supported copper catalyst. Aiming at enhancing the ethanol selectivity for this two-step approach, we developed a 0.1Pt-Cu/SiO2 single-atom alloy catalyst in the present work where Pt was isolated as single atoms and formed Pt-Cu alloy phase. The characterizations of the catalyst with in situ XRD, FT-IR, CO-adsorbed DRIFTS, N2O chemisorption and XPS revealed that the introduction of 0.1 wt% Pt resulted in improvement in the Cu dispersion and an increase of Cu+/Cu0 ratio, meanwhile the Pt single atoms promoted the activation of hydrogen. As a consequence, the catalytic activity and selectivity of ethanol were enhanced; the maxinum selectivity of ethanol (76.7%) was obtained at 503 K. Over a 700 h time on stream the catalyst did not show any deactivity, demonstrating a proming stability.