In this study, the methanol steam reforming reaction was carried out in a carbon membrane reactor (CMR) for hydrogen production. The behavior in the CMR was compared to that in a fixed-bed reactor (FBR) at the same experimental conditions. The parameters temperature, carrier gas flow rate, and feed ratio were investigated to better understand the separation effect of hydrogen in the CMR on the methanol conversion and product selectivity. The results showed that the CMR gives a higher methanol conversion than the FBR at all investigated operating conditions; the overall yields of hydrogen in the CMR and FBR are identical, but a CO-free hydrogen stream can be produced with the CMR, which could be directly used in a proton-exchange-membrane fuel cell.