Abstract: A parallel flow model of isothermal one-dimension pseudo-homogeneous membrane reactor for methanol synthesis from CO ₂ in silicone rubber/ceramic composite membrane reactor was developed. Runge-Kutta method was adopted to simulate the process behavior in the membrane reactor. Such parameters which affect the reaction behavior in the membrane reactor,as operation parameter, Damkhler number Da , pressure ratio p _r, reaction temperature T , membrane separation α , membrane permeation parameter Φ , mole ratio γ of H ₂ to CO ₂, flux ratio q ₁ of purge gas to feed as well as L ₁ the nonuniform parameter of membrane permeation, were discussed in detail.