Graphene Oxide (GO) flakes were fabricated via a modified Hummer’s method. Polyacrylonitrile (PAN) was applied to metal adsorption. PAN was chemically modified with amidoxime groups, which are suitable for metal adsorption due to their high adsorption affinity for heavy metal ions. Layer-by-layer self-assembly method is used to fabricate GO-Polymer composite membrane. The selective metallic penetration of organic solvents and water in large contact area, high pressure standing, and hermetically (liquid tight) sealed graphene oxide (GO) membranes and GO-polymer composite membranes are demonstrated. The water purification properties of GO-polymer composite membranes are discussed. Interestingly, composite membrane forms a better property of absorption to copper and lead ions and obstruction to sodium ion. Furthermore, the penetration results revealed that sodium salts can be separated effectively from copper and lead salts contaminants. The mechanism of the selective ion-penetration properties of the composite membrane is discussed. Finally, the presented results demonstrate the potential applications of GO-Polymer in area such as barrier separation and water purification.