Abstract: Graphene is a new type of carbon material with zero band gap structure,extremely low resistivity and high transmittance.The excellent optical properties,electrical properties and photoelectric properties of graphene make it a fine material for the next generation of high frequency,ultrafast and wide spectrum photoelectric devices.At present,many photodetectors based on graphene are developed.In this paper,the properties and structures of graphene are briefly introduced with basic principles of photodetectors,then focus are put on the application and research status of functionalized graphene in photodetectors moreover,the existing deficiency and the future development direction are pointed out.