Abstract: Graphene oxide (GO) has a large number of oxygen-containing functional groups on the basal planes and edges, which makes easily dispersed in water and broadens its prospective use. In-situ polymerization, a common polymerization technique, is widely used in the synthesis of graphene/polymer nanocomposites. This paper considers the different preparation methods of graphene and graphene oxide, and the basic principle of in-situ polymerization and its use in the preparation of graphene or GO/polymer nanocomposites, including GO/polyimide, GO/epoxy, GO/polyurethane, GO/polystyrene, graphene/polyaniline, GO/polyaniline, GO/polyvinyl alcohol and GO/polydopamine.