The electroconductive graft copolymer Poly(vinyl chloride)-g-poly(aniline) (PVC-g-PANI) was prepared by the electrochemical polymerization using a precursor as follows: The precursor polymer, poly(vinyl 1,4-phenylenediamine)(PVPD) dissolved in DMF was spin coated on a platinum electrode and polymerized electrochemically in the electrolytic mixture solution consisting of DMF water, 0.1 M aniline, and 1.0 M electrolyte such as H2SO4, HCl, or HNO3. PVPD was synthesized chemically with PVC and potassium 1,4-phenylenediamine salt and characterized using FT-IR and H-1-NMR spectroscopy. The electrochemical properties such as cylclic voltammetry and chronoamperogram of PVC-g-PANI were investigated comparing with those of PVC/PANI composite.