Micro-channel plates with dimension of 1 mm ร 0.3 mm ร 48 mm were prepared by chemical etching of stainless steel plates followed by wash coating of CeO 2 and Al 2 O 3 on the channels. After coating the support on the plate, Pt, Co, and Cu were added to the plate by incipient wetness method. Reaction experiments of a single reactor showed that the micro-channel reactor coated with CuO/CeO 2 catalyst was highly selective for CO oxidation while the one coated with Pt-Co/Al 2 O 3 catalyst was highly active for CO oxidation. The 7-layered reactors coated with two different catalysts were prepared by laser welding and the performances of each reactor were tested in large scale of PROX conditions. The multi-layered reactor coated with Pt-Co/Al 2 O 3 catalyst was highly active for PROX and the outlet concentration of CO gradually increased with the O 2 /CO ratio due to the oxidation of H 2 which maintained the reactor temperature. The multi-layered reactor coated with CuO/CeO 2 showed lower catalytic activity than that coated with Pt catalyst, but its selectivity was not changed with the increase of O 2 /CO ratios due to the high selectivity. In order to combine advantages (high activity and high selectivity) of the two individual catalysts (Pt-Co/Al 2 O 3 , CuO/CeO 2 ), a serial reactor was prepared by connecting the two multi-layered micro-channel reactors with different catalysts. The prepared serial reactor exhibited excellent performance for PROX.