In this work, graphene oxide was prepared by a modified Hummers’method. Then, it was used as a support for preparation of nanoparticles.Pt-Ni-Sn nanoparticles were synthesized on the reduced graphene oxide(RGO) support by a chemical reduction method. The catalytic activity ofPt-Ni-Sn/RGO nanocomposite was investigated for ethanolelectrooxidation through cyclic voltammetry method. Different parametersaffecting on ethanol oxidation at Pt-Ni-Sn/RGO catalyst were investigated.The results showed that the catalytic activity of Pt/RGO nanocompositetowards ethanol oxidation was improved by the addition of Ni and Snnanoparticles. The improvement of the catalytic activity depends on theamount of Sn and Ni nanoparticles. The catalytic activity of Pt-Ni-Sn/RGOcatalyst for ethanol electrooxidation was significantly higher than that ofPt/RGO, Pt-Sn/RGO and Pt-Ni/RGO catalysts.