Using platinum and lead dioxide electrode, anodic process of pinacol have been investigated with potentiostatic method in various pH. Experimental results indicate that yield of acetone from pinacol is good in acidic region and electrolytic products is pH dependent. In this paper, we studied that Tafel slope for the oxidation of 0.5 M pinacol solution buffered to pH 1.2 in order to investigate the mechanism of C-C bond cleavage reaction of pinacol. Results of Tafel slope indicate that electrochemical oxidation of pinacol is electron-electron（E-E） mechanism.