A novel hydrophilic organo-inorganic composite membrane was prepared by graft-polymerization of acrylamide on a microporous silica membrane, preliminary silylated by gamma-(methyl acryloyl) propyl tri-methoxysilane. The surface properties and morphology of the membrane were analyzed by means of SEM, AFM, FTIR and TGA. The influence of monomer concentration on membrane performances for dehydration of ethanol was systematically studied. It was found that the membrane was very selective and permeable for dehydration of alcohol and acrylic acid. The membrane grafted in 3% of AM has good separation performances. The influence of feed concentration and operation temperature on membrane permeation is special.