The interaction of the single azo dye, carmine with ﬁsh-sperm dsDNA is inspected in pH 3.2 H2SO4 with electrochemical method on the surface of nanometer TiO2 modified carbon paste electrode. After the addition of dsDNA, the peak currents of oxidation and reduction peaks of carmine decrease with a positive shift of potential, indicating that intercalation interaction between the dye and dsDNA is taken place. This is consistent with ﬂuorescence spectra results. The binding constant and binding ratio is calculated as 4.92×108 and 1:2, respectively. Furthermore, the decrease in the oxidation peak currents is found proportional to dsDNA concentration in the range of 21.24-127.44 μg·mL-1 with a detection limit of 16.04 μg•mL-1.