Pd-Ag/ceramic composite membrane, which was prepared by improved electroless plating with osmosis , exhibited higher hydrogen flux,reaching 0.619 mol·s -1 ·m -2 (673 K,Δ p =0.196 MPa). The catalytic dehydrogenation of isobutane in the Pd-Ag/ceramic composite membrane reactor was studied. The effects of various operating parameters,such as reaction temperature, linear velocity of feed gas, linear velocity of purge gas, molar ratio of nitrogen to isobutane in feed gas, and pressure of feed gas on conversion of isobutane were investigated. It was observed that the conversion of isobutane (50.5% at 723 K) in the membrane reactor exceeded the equilibrium conversion (18.8% at 723 K) and that in the fixed-bed reactor (15.5% at 723 K). From experimental results for dehydrogenation of isobutane in the membrane reactor, it was found that when a certain partial pressure of hydrogen was maintained in the reaction-side of the reactor, the formation of accumulative carbon overlayers on the surface of dehydrogenation catalyst and membrane was inhibited to some extent, which reduced the deactivation rate of catalyst and membrane. Pd-Ag / ceramic composite membrane, which was prepared by improved electroless plating with osmosis, exhibited higher hydrogen flux, reaching 0.619 mol · s -1 · m -2 (673 K, Δ p = 0.196 MPa). The catalytic dehydrogenation of isobutane in the Pd-Ag / ceramic composite membrane reactor was studied. The effects of various operating parameters, such as reaction temperature, linear velocity of feed gas, linear velocity of purge gas, molar ratio of nitrogen to isobutane in feed gas, and pressure of It was observed that the conversion of isobutane (50.5% at 723 K) in the membrane reactor exceeded the equilibrium conversion (18.8% at 723 K) and that in the fixed-bed reactor (15.5% at 723 K). From experimental results for dehydrogenation of isobutane in the membrane reactor, it was found that when certain certain pressure of hydrogen was maintained in the reaction-side of the reactor, the formation of accumulative carbon overlayers on the surface of dehydrogenation catalyst and membrane was inhibited to some extent, which reduced the deactivation rate of catalyst and membrane.