Methanol steam reforming over a CuO-CeO₂ catalyst was studied using a packed-bed reactor at atmospheric pressure in the temperature range of 160-280 ℃. The reaction products were carbon dioxide and hydrogen with a small amount of carbon monoxide, always less than the amount of the water-gas-shift equilibrium, confirming that the carbon dioxide and hydrogen were directly produced by the reaction. The methanol conversion was not affected by the carbon dioxide concentration and the water concentration in the feed as long as the water concentration was in excess of the stoichiometry. The reaction rate depended on the reaction temperature and partial pressures of methanol and hydrogen. The catalyst showed a slow but steady deactivation during the course of reaction over 220 hours. For the fresh catalyst and the catalyst aged for 220 hours, power-law rate and Langmuir-Hinshelwood rate expressions were determined from an integral analysis of the packed-bed reactor, in which the effectiveness factor of the catalyst particle was also accounted for. Activation energy of the reaction was 106-108 kJ/mol for the fresh catalyst and 83 kJ/mol for the aged catalyst. A reaction mechanism that dehydrogenation of the methoxy species is the rate determining step and hydrogen adsorption occurs on an exclusive kind of sites different from the sites for other adsorbed species was proposed based on the analysis of the experimental data.