The calculation models of flow and combustion were established for a segmental catalytic micro channel incorporated with detailed hydrogen-oxygen gas-phase and surface reaction mechanisms. The aim of the study was to realize the effects of surface catalyze reaction on gas-phase reaction at different flow velocities, equivalence ratios and channel heights. The results showed that the surface catalytic reaction strengthened gas phase reaction in the downstream of catalytic segment along with the increase of inlet flow velocity. The heat released from surface reaction resulted in a temperature gap between the inner up and down walls, and this temperature gap was increased with the increase of inlet flow velocity in the domain of the front 2 mm, but it vanished gradually because of the dominant gas-phase reaction in the downstream. Due to the competition of OH radical between two reactions, a fit equivalence ratio about 1 contributed to enhancing the gas phase reaction. On the contrary, surface reaction obviously restrained the gas phase reaction when the fit equivalence ratio was too small or big. It restrained gas reaction in the domain of catalyze surface and increased the outer wall’s temperature when keeping a constant mass flow rate and a lower height channel. But it had little influence on surface reaction.