Biomass-based carbon nanofibers were prepared by double-nozzle electrospinning the aqueous solution of acid treated the waste medicine Aconitum sinomontanum Nakai extraction and polyacrylonitrile 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.