The shortage of water resources is a problem concerned by all countries in the world. In order to solve this problem of human survival, membrane separation technology promotes the development of water treatment field by virtue of its own advantages of high efficiency and low consumption. Membrane separation technology combined with nanomaterials has brought surprises to researchers. Graphene has unique structure and properties, making graphene and its derivatives have very good potential in water treatment and selective separation. Graphene-based materials combined with traditional polymer materials have great potential in the field of membrane separation technology. In this article, we first introduce the preparation methods and transport mechanism of graphenebased membranes, and then summarize the recent applications of graphene oxide/polymer composite membranes in water purification, gas separation, self-cleaning, and oil-water separation. It is expected to become the next generation of functional composite membranes.