High-performance hybrid supercapacitor is still hampered by lacking of proper electrode materials of desired nanostructures. However, the hybridization of polyaniline (PANI) on functionalized reduced graphene oxide (FrGO) could form such desired nanostructure with uniform graphene distribution, high carriers density and significantly improved cycling stability and rate capability of PANI. Here we report a facile process for the hybridization of polyaniline nanofibers (PANI NFs) on functionalized reduced graphene oxide (FrGO) films by filtering the hybrid suspension of graphene oxide (GO) and in-situ polymerized PANI NFs followed by hydrothermal treatment to reduce GO and sulfur functionalization of rGO. The as-prepared PANI NFs/FrGO composite films were uniform, flexible and stable with a high specific capacitance of 692.0 F/g at 1 A g(-1) and an excellent capacitance retention of 53.5% at 40 A g(-1). Furthermore, the assembled all-solid-state supercapacitor using the as-prepared composite films as electrodes exhibited a high capacitance of 324.4 F/g at 1 A g(-1) and an energy density similar to 16.3 Wh kg(-1) at a power density of 300 W kg(-1), showing a great promising in the applications for portable power and flexible supercapacitor. (C) 2018 Elsevier Ltd. All rights reserved.