Catalytic activities of Ce-Mg promoted Cu/Al2O3 catalysts via methanol steam reforming was investigated in terms of the methanol conversion level, carbon monoxide selectivity and hydrogen yield. The factors chosen were the reaction temperature, copper content, Mg/(Ce + Mg) weight-percentage and steam to carbon ratios. The catalysts were prepared by co-precipitation and characterized by means of XRD, BET, H-2-TPR, and FESEM. The Ce Mg bi-promoter catalysts gave higher performance due to magnesium penetration into the cerium structure causing oxygen vacancy defects on the ceria. A response-surface model was then designed to optimize the condition at a 95% confidence interval for complete methanol conversion to a high H-2 yield with a low CO content, and revealed an optimal copper level of 46-50 wt%, Mg/(Ce + Mg) of 16.2-18.0%, temperature of 245-250 degrees C and S/C ratio of 1.74-1.80. No deactivation of the Cu0.5Ce0.25Mg0.05/Al catalyst was observed during a 72-h stability test. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.