Electrochemical properties of dodecylbenzenesulfonic acid-doped polyaniline film (PAn-DBSA) were investigated by cyclic voltammetry in an organic mixture solution of propylene carbonate-1,2-dimethoxyethane containing 1 M LiClO4. The PAn-DBSA film showed reversibility and electrochemical stability over 500 cycles in the redox process. Its electrochemical stability was explained by the ionic replacement of DBSA anions with ClO4- anions and by the deprotonation during the redox process. This behavior was confirmed from the results obtained using cyclic voltammetry and energy-dispersive X-ray spectroscopy (EDXS).