Abstract: A highly efficient cerium-modified Cu/hexagonal mesoporous silica (xCe-Cu/HMS) catalyst for the vapor-phase hydrogenation of dimethyl oxalate (DMO) into ethylene glycol (EG) was prepared using an ammonia evaporation method. The Ce promoter can significantly improve the performance of the catalyst, and the best catalytic performance was obtained after the introduction of 1.2% Ce promoter on Cu/HMS. The DMO conversion and EG selectivity got to 99.6% and 96.3%, respectively, under moderate conditions (200 °C, 2.0 MPa, H₂/DMO = 100 and LHSV_DMO = 1.2 h⁻¹). Characterization results revealed that Ce modification can enhance the interaction between Cu and the support, improve the dispersion of Cu on HMS, and maintain the appropriate ratio of Cu⁺/(Cu⁺+Cu⁰). In this study, a simple and low-cost method was used to synthesize Ce-modified Cu-HMS catalysts, which showed excellent catalytic performance in conversion of DMO to EG under moderate conditions.