Abstract: Cu/reduced graphene oxide (RGO) photocatalytic composites were prepared through the liquid phase chemical method by using cupric acetate and graphene oxide (GO) as the precursors and ascorbic acid as the reducing agent. The Cu/RGO composites were characterized by XRD, SEM, TEM, FTIR and Raman, the photocatalytic performance of composites toward methylene blue was investigated under the aid of H₂O₂. The results show that the Cu particles uniformly distribute on the RGO sheets, and the Cu/RGO composite exhibites good catalytic activity for the decolorization of methylene blue. The Cu/RGO composite shows the best catalytic performance for MB when the composite dosage is 0.06 g/L, the decolorization rate reach 92.5% in 200 min, and the decolorization rate remains 88.0% after 5 cycles.