It was investigated whether an electrode could serve as an electron donor for biological reductive dechlorination of chlorinated phenols in the bio-electrochemical process. There was no dechlorination in the absence of current and scanning electron microscope image showed that the electrode surface was covered with microorganisms. As a result, the electrode attached cells was responsible for reductive dechlorination. Also, initial high chlorinated phenol concentration such as $437mg/{ell}$ was rapidly reduced within 5 hours. The maximum dechlorination rate using Monod equation was $5.95mg{ell}$-h($cm^2$ (electrode surface area)) in the bio-electrochemical reactor.