Gas sweeping pervaporation has the advantages of no limitation of membrane configuration and its mechanical strength in operation. A permeation model of pervaporation processes is presented, which incorporates a hypothetical liquid concentration in equilibrium with a permeant concentration in the membrane phase as well as in the ps phase. On the basis of the simple model, an overall mass-transfer coefficient for the transmembrane process can be obtained from the individual transfer coefficient, which facilitates the designing of the pervaporator. The application of this method was examined on the pervaporation of ethanol and isopropanol from the respective aqueous solutions across a poly(dimethylsiloxane) hollow fiber membrane using nitrogen as the sweeping carrier gas. The solubility and diffusion coefficients of the two alcohols in the membrane were also measured. The permeation data are in agreement with the model predictions.