In this paper, nichrome was adopted as a substrate, to fabricate the pre-anodized inlaying ultrathin carbon paste electrode (PAIUCPE). The electrochemical behaviors and diffusion mechanisms of three dihydroxybenzene isomers at the electrode were carefully investigated. The effect of pH on oxidation peak current was also detailedly explained. The results were shown that oxidation peak current not only related to the reaction of electroactive materials at the working electrode, but also depended on the reaction variable of reduction at the auxiliary electrode. mol/L, respectively. The proposed method was successfully applied in the simultaneous determination of dihydroxybenzene isomers in artificial sewage samples with satisfactory results.