Abstract: A DNA/ZrO₂/MWCNT/GCE electrochemical sensor was prepared based on the zirconia thin porous film fabricated by cyclic voltammetric method in an aqueous electrolyte at room temperature. Because of the high sepecific surface of MWCNT, favorable electron transfer properties, biocompatibility of zirconia and high adsorption capacity of DNA, the immobilization of DNA probe and detection sensitivity of DNA hybridization were promoted.Using methylene blue(MB) as redox indicator, DNA immobilization and hybridization were characterized by cyclic voltammetry and differential pulse voltammetry. The sensor showed high sensitivity and good linearity, the peak current of MB was linearly related to the concentration of the target DNA in the range 2.15×10^-7to 2.15×10^-10 mol/L with the detection limit of 6.58×10^－12 mol/L.