New materials with good antibacterial activity synthesized by simple, environmentally friendly method have attracted numerous research interests. Taking advantage of Ag and graphene oxide(GO), the GO/Ag nanocomposites were prepared by a facile, green ‘‘one-pot’’ reaction to achieve superior antibacterial properties. Ag NO_3 is as a precursor of Ag nanoparticles(Ag NPs), and the grape seeds extract as an environmentally friendly reducing and stabilizing agent. The asprepared GO/Ag nanocomposites were characterized by various technologies. The results indicated that the silver ion was reduced by the grade seeds extract and Ag NPs were decorated on the surface of GO nanosheets successfully. The average size of the Ag NPs anchored on the GO surface was 40–50 nm. In this study, we prepared GO/Ag nanocomposites with different Ag NPs to GO ratios and carefully investigated their antibacterial activities. We found that the GO/Ag nanocomposites show better antibacterial activity when the concentration of Ag NO_3 is 2 m M. GO/Ag nanocomposites have a minimum inhibitory concentration 23.8 lg/m L, lower than bare Ag NPs 25.5 lg/m L. We try to explain the antibacterial mechanism based on optical microscopy observation. New materials with good antibacterial activity synthesized by simple, environmentally friendly method have been numerous numerous research interests. Taking advantage of Ag and graphene oxide (GO), the GO / Ag nanocomposites were prepared by a facile, green ’one-pot’ ’reaction to achieve superior antibacterial properties. Ag NO_3 is as a precursor of Ag nanoparticles (Ag NPs), and the grape seeds extract as an environmentally friendly reducing and stabilizing agent. The asprepared GO / Ag nanocomposites were characterized by various technologies. the silver ion was reduced by the grade seeds extract and Ag NPs were decorated on the surface of GO nanosheets successfully. The average size of the Ag NPs anchored on the GO surface was 40-50 nm. In this study, we prepared GO / Ag nanocomposites with different Ag NPs to GO ratios and carefully investigated their antibacterial activities. the we found that the GO / Ag nanocomposites show better antibacterial activity when the concentration of Ag NO 3 is 2 m M. GO / Ag nanocomposites have a minimum inhibitory concentration of 23.8 lg / m L, lower than bare Ag NPs 25.5 lg / m L. We try to explain the antibacterial mechanism based on optical microscopy observation.