Pervaporation of water-ethanol mixtures through acrylamide-plasma graft-polysulfone (AAm-p-PSF), a PSF membrane on which AAM is grafted by plasma polymerization, was investigated in this work. The effects of plasma treatment conditions and feed compositions on the pervaporation performances were studied for the un-ionized and ionized AAm-p-PSF membranes. It was found that the separation factor of the AAm-p-PSF membrane is higher than those of the unmodified membranes. The ionized membrane possesses a sep separation factor of 10.4 and a permeation rate of 718.1 g/m(2) h. In addition, the surface properties of the prepared membrane were characterized by ESCA, SEM, and a water contact angle meter; and the relationship between the grafting yield and the plasma pretreatment time was obtained.