Combining polyaniline (PANI) with different dimensional carbon materials is an effective way to solve the disadvantages of poor rate performance and cycling stability induced by the structure destruction of conductive polymer materials over long-term charge/discharge cycles. In this work, novel three-dimensional (3D) conical PANI nanothorns are synthesized on a buckypaper substrate via a controlled electropolymerization process. Benefiting from the synergistic effect of the vertical growth of PANI nanothorns and the excellent mechanical elasticity of multi-wall carbon nanotubes, it can effectively alleviate the volume change during the charging and discharging process of the electrode material and ensure the rapid transmission of electrons. The morphology and structure of the composite have been characterized by scanning electron microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The results show that the electrode exhibits a high specific capacitance of 742 F g-1 at 1 A g-1 in 1 M of H2SO4 electrolyte and a capacitance retention of 76% after 2000 cycles. The novel 3D PANI nanothorn/buckypaper composite has significant potential as practical for use as electrode materials of supercapacitors due to its easy synthesis, low cost, and high specific capacitance.