In order to establish the reaction conditions for producing carbon nanofibers by passing a commercial propane gas over Cu-Ni and Ni catalysts, the experimental conditions such as catalyst composition, reaction temperature and gas flow rate were varied. It was observed by SEM that the obtained carbon deposits were mainly composed of carbon nanofibers with the diameters ranging 50-300 nm. The carbon yield and structure were dependent on the catalyst composition and reaction temperature. The maximum yields of carbon nanofibers from propane decomposition were obtained at temperatures from 650 to 700℃ and the higher yields were obtained over the alloy catalysts containing 50-90 wt% nickel than the pure nickel catalyst. The specific surface area and electric resistivity were measured as the key properties for the electrode application of a double layer capacitor(DLC). The carbon nanofibers from Cu-Ni catalyst had relatively high surface areas of around 350 m²/g, while those from Ni catalyst showed about 150 m²/g of surface areas. The electrical resistivity was also dependent on the catalyst composition, raging 0.05-0.25 Ω·cm and these values were much lower than those for activated carbon which is currently used as the electrode materials.