A composite palladium membrane consists of a thin film of palladium layer coated on a ceramic support. Two kinds of models are formulated for the direction of permeation through the composite membrane (CP mode and PC mode). The apparent order of hydrogen pressure is varied from 0.5 to 1.0 by the relative values between two resistances of palladium film and ceramic support for the hydrogen permeation rate through the composite membrane. The relation between the apparent order and the relative resistance is dependent on the operating conditions. Once the apparent order can he determined from the linearity of experimental data, we can estimate the relative resistance.