The mechanism of methanol steam reforming for hydrogen-making over CuO/ZnO/CeO2 / ZrO2 is investigated by in situ FT-IR.The experimental results show that methanol steam reforming for hydrogen-making consists of methanol dehydrogenation,methyl formate hydrolysis and reverse water gas shift(RWGS).The by-product CO formation is mainly due to the RWGS reaction,which is the reason that the CO level in the reforming gas is below the equilibrium concentration.