Graphene has received extensive attention due to its excellent properties, and is considered to have broad application prospects in the fields of material processing, energy, biomedicine and drug delivery. Recently, graphene and its composite materials have been gradually applied to wastewater treatment. Here, different graphene composites and their properties are outlined. The application of graphene and its composites as adsorbents and catalysts in typical wastewater treatment (such as dye wastewater, heavy-metal wastewater, oily wastewater, refractory organic wastewater) is reviewed. The treatment efficiency and treatment mechanism of different graphene composites are summarized and analyzed. Finally, reasonable comments and suggestions are raised about the existing problems in wastewater treatment applications. And the outlook for and the future development of graphene and its composites were discussed.