In order to investigate the effects of inlet temperature,velocity and water methanol molar ratio on methanol- steam reforming for hydrogen production in microreactor, we carry out 3-D simulation of methanol-steam reforming for hydrogen production in self-designed plate microreactor with the application of general finite reaction rate model in CFD software of FLUENT, The kinetics used are DE and SR model, The results show that, At the conditions of inlet velocity, temperature and water methanol molar ratio are 2.88 m/s, 493 K and 1.3 respectively, methanol conversion at the reactor outlet reaches 79.8%. Through the simulation, we can see that in microreactor it can be maintain higher hydrogen molar fraction and methanol conversion at high reactant flow rate.