Abstract: Electro reduction of 3,3′,4′, 5,7 pentahydroxyl flavone was studied using cyclic voltammetry. In ethanol water solution only one peak was observed while in DMF two peaks were found, each peak corresponding to a one electron reduction. ESR spectroscopy technique was applied in situ to the study of the flavone jointly with the electrolysis. Hyperfine structures of ESR spectrum of the electrochemically generated free radical of flavone in DMF were observed for the first time. Relative parameters of the ESR signals were obtained through calculation. The g factor was found to be 2 006, different hyperfine coupling constants were 2 78, 1 61 and 0 60Gs.