Abstract: Styrene butyl acrylate copolymer (SBA) was prepared by emulsion polymerization. The reduced graphene oxide-SBA/polymethyl methacrylate (rGO-SBA/PMMA) composites were fabricated through melt blending method. The structure of the rGO-SBA/PMMA composite was characterized by FTIR, TGA and dynamic mechanical analysis, and the dielectric properties of the composites were tested. The results show that the addition of rGO can increase the glass transition temperature of SBA. At the same time, it can enhance the thermal stability of rGO-SBA composites. Moreover, the addition of rGO significantly increases the dielectric constant of the rGO-SBA composites. rGO-SBA composite possesses the property of high dielectric. For rGO-SBA/PMMA composites, when the SBA content is 13wt% and the rGO content is 0.52wt%, the dielectric constant can approach to 8.79 and the dielectric loss is as low as 0.37 at 1 000 Hz, which further shows that the rGO-SBA/PMMA composites have the characteristics of high dielectric constant and low dielectric loss.