As the key material for flexible electronics, free-standing supercapacitor electrodes have attracted great research interests in recent years. However, constructing the novel supercapacitor electrodes with excellent mechanical properties and high areal capacitance remains a challenge. This study demonstrates the fabrication of a highly flexible and mechanically robust supercapacitor electrode based on combination of aramid nanofibers (ANFs), multi-walled carbon nanotubes (MWCNTs), and polyaniline (PANI) in form of nanostructured composite film. The ANFs/MWCNTs/PANI film electrode obtained via vacuum-assisted layer-by-layer (VA-LBL) assembly technique achieves a tensile strength of 158.7 MPa and an areal specific capacitance of 497.3 mF cm⁻² at a current density of 0.25 mA cm⁻², showing an outstanding compatibility between high electrochemical performance and superior mechanical properties. In addition, the ANFs/MWCNTs/PANI film electrode exhibits an excellent cycle life with 89% capacitance retention after 3000 cycles. Synergistic effect from the strategic assembly of ANFs, MWCNTs and PANI in form of a single nanostructured platform makes this kind of free-standing electrode applicable for flexible and solid-state energy storage systems.