On the basis of the six-wafer combustor used in a micro-gas turbine engine developed by Massachusetts Institute of Technology(MIT),a two-dimensional Computational Fluid Dynamics(CFD) simulation was employed in studying the effect of hydrogen/air ratio on the combustion performance in a micro combustor when the mixture mass flow rate was fixed.The CFD modeling includes the hydrogen/air flow path,combustion chamber as well as the solid walls of the micro-combustor,and the simulation analysis involves in the flow mechanics,heat transfer and the numerous chemical reactions occuring in the micro-combustor.The results show that the flame will be quenched finally in the chamber when the equivalence ratio of fuel/air mixture is 0.4 and the combustion is more stable when the equivalence ratio of fuel/air mixture is 0.5 or 0.6;the flame front will propagate to the upstream of the fuel/air mixture flow,burning in the recirculation jacket when the equivalence ratio is increased to 0.7.It comes to a conclusion that the present numerical simulation is helpful for the design and improvement of the micro-combustor.