Abstract: An experimental investigation focusing on the interaction between surface catalytic reaction and thermal hydraulics is carried out. Analysis is conducted on the effects of different inlet velocities and hydrogen concentrations on the chemistry and thermal hydraulics. From the experiment results, it can be found that the distribution of catalytic temperature at first half of the sheet is higher than that of the second half. With the increasing of the inlet velocity, the outlet hydrogen concentration also increases. Relative to the inlet hydrogen concentration, the effect of inlet velocity exerted on outlet temperature and catalytic temperature are not monotonous. As inlet hydrogen concentration increases, outlet hydrogen concentration, along with catalytic temperature would increase therewith.