Carbonaceous thin films were prepared from acetylene and argon by plasma CVD. The carbon thin films were characterized by Raman spectroscopy and then their electrochemical properties were studied by cyclic voltammetry and charge-discharge measurements. Crystallinity of the films prepared at 90W was much higher than that at 10W. The difference of the applied RF power also effected on the results of cyclic voltammetry and charge-discharge measurements. Correlation of applied RF power and the electrochemical properties of carbon thin films was discussed.