Biomass-based carbon nanofibers were prepared by double-nozzle electrospinning the aqueous solution of acid treated the waste medicine Aconitum sinomontanum Nakai extraction and poly-acrylonitrile followed by thermal treatment in an inert atmosphere. The structural, constituent and surface properties of biomass-based carbon nanofibers were investigated by means of spectroscopic, microscopy, energy spectrometer and Brunauer-Emmet-Teller (BET) techniques. The results showed that the biomass-based carbon nanofibers had abundant pore structure and large specific surface area. The electrochemical performance of supercapacitor electrodes with the nanofibers was studied. This electrode showed a capacitance of 295 F/g at the current density of 1 A/g in 6 mol/L aqueous KOH electrolyte, and 98.5% capacity retention after 1000 charge/discharge cycles at the current density of 2 A/g. This indicate that the activate biomass-based carbon nanofibers have a good electrochemical stability.