Graphene based nanocomposites have attracted great deal of attention because of exhibiting high performance as electrode materials for supercapacitor applications. Herein, ternary reduced graphene oxide (rGO) - Au nanoparticles (Au NPs)@polyaniline (PANI) nanocomposite was prepared with a two-step, low-cost, and green approach. In the first step, graphene oxide (GO) was reduced and stabilized by Cetraria Islandica L. Ach lichen extract. Then, the rGO nanosheets were homogeneously coated with interconnected Au@PANI ultrafine film via in-situ polymerization of aniline monomer by using HAuCl4 as an oxidizing agent. rGO-Au@PANI nano composite show a high specific capacitance of 212.8 F/g at current density of 1 A/g in two-electrode configuration. Moreover, the nanocomposite electrodes exhibit 86.9% specific capacitance retention after 5000 cycles.