This research aims to design a heat-exchanger type of methanol reformer by using gPROMS® . The endothermic methanol steam reforming reaction (MSR) and the exothermic preferential oxidation reaction (PROX) occur in the inner tube and the outer tube of the reformer, respectively. The effective heat transfer rate between the inner and outer tubes through the wall is guaranteed. The simulation shows that the counter-current type reformer provides the higher hydrogen yield than the co-current type. Since the hot spot temperature appears in the outer tube, the authors propose an improved scheme to suppress the hot spot temperature by splitting the excess air flowing into two sites. Finally, an optimization algorithm for maximizing the hydrogen yield is employed to determine optimal operating conditions.