Hydrophilic/hydrophobic, cationic/anionic hetero geneous IPN membranes as well as hydrophilic/hydrophilic homogeneous IPN membranes were prepared and the prevaporation characteristics of the membranes for the separation of ethanol/water mixture were elucidated. The computer simulation of the continuous rectangular prevaporator was conducted and the membrane characteristics for the optimum performance was analyzed. The IPN membrane characteristics were estimated based on the heterogeneous and homogeneous model and the predicted properties were compared with experimental data.