Abstract: Ultraviolet(UV) irradiation method was introduced to label the defects of graphene via the interaction between the Ag nanoparticles and oxygen-containing functional groups.Resultsshow that Labeling Ag nanoparticles can provide information about the density and locations of the defects and offere new possibilities for preparation of Ag nanoparticles modified graphene in a simple way. Furthermore,the conductivity of the graphene can be improved by Ag nanoparticles.