Abstract: The kinetics of isotopic exchange reaction between hydrogen and water vapor over Pt-SDB as a hydrophobic catalyst was investigated in a fixed co-current bed. The influence of various factors on the rate constant of water vapor-hydrogen co-current exchange reaction were studied, including rate equation, order of reaction, temperature dependence of reaction and the species of catalysts. The results show that the overall reaction is first order. The relation of apparent rate constant with temperature accorded with Arrhenius and the apparent rate constant increases with temperature rising. The apparent activation energy of Pt-SDB is lower than Pt-C-PTFE and the rate constant of water vaporhydrogen cocurrent exchange reaction increases when the apparent activation energy of the hydrophobic catalyst decreases.