The compatibility of poly (vinyl alcohol)-chitosan blends was tested and analyzed by their glass transition temperatures with differential scanning calorimetry with a DSC-7 (Epson). Highest selectivity, promising permeability and good mechanical strength for the dehydration of alcohol-water mixtures were obtained at a 4:1 composition of the blend. The chemical composition, physical structure and morphology of this blended composite membrane were studied by a variety of surface science techniques, including infrared spectrometry (IR), small-angle X-ray diffraction (SAXRD) and scanning electron microscopy (SEM). The surface investigation is needed-for the study of the blended composite membrane, and the results confirm well with the characteristics of the new membrane.