A new carbon nanotubes and cupric hexacyanoferrate modified electrode（MWCNTs-CuHCF/GCE） was prepared by drop coating and electropolymerization.The properties of electrode surface were characterized by Nyquist plots.The electrochemical behaviors of α-N and β-N on MWCNTs-CuHCF/GCE was investigated by cyclic voltammetry（CV）.Influences of type of buffer solution，pH value，amount of MWCNTs,electropolymerization of CuHCF and scan rate were discussed.The results indicated that there were two obvious oxidation peaks of α-N and β-N appearing at 0.335 V and 0.505 V，respectively.The oxidation peaks of α-N and β-N were completely separated and the oxidation peak currents of both α-N and β-N were linear with scan rate（v） in the range of 40-220 mV/s，which showed that the electrode processes of α-N and β-N were controlled by adsorption.The electron number（n），proton number（m），adsorption capacity（Γ）and effect area（A）of the modified electrode were studied.Under the optimal conditions，the differential pulse voltammetry（DPV）with derviative technique was used to determine naphthol isomers quantitatively.Good linear relationships between peak currents and concentrations of α-N and β-N were observed in the range of 0.5-100 μmol/L（rα-N=0.992；rβ-N=0.996）.The proposed method was applied in the determination of α-N and β-N in water samples with spiked recoveries of 94.2%-105.7%and 90.2%-103.3%,respectively.