A new alcohol dehydration membrane, poly(vinyl alcohol)—chitosan blended composite membrane (PVA-CS) has been prepared. This membrane has high selectivity and promising permeability, especially in separating ethanol—water near the azeotropic region ( J t > 200 g/m 2 h, α w e > 500, 70°C). The separating characteristics, which vary with feed composition, operating temperature and the surface structure of the membrane, are determined and the results agree well with the theoretical predictions. The characteristics of mechanical strength, stability and resistance to water were also determined. The results show that they are considerably enhanced by blending and crosslinking, in comparison with PVA composite membranes.