The recognition interaction of rhodamine B (RB) with DNA was studied in pH 7.5Britton-Robinson (B-R) buffer solution by electrochemical techniques. An irreversible oxidation peak at glassy carbon electrode was obtained at +0.92V (vs. SCE). After the addition of DNA into the RB solution, the peak current of RB decreased apparently without the shift of peak potential. The electrochemical parameters such as the charge transfer coefficient α and the electrode reaction standard rate constant ks of RB in the absence and presence of DNA were determined, which did not change, indicating that a non-electroactive complex was formed, so the concentration of RB in the solution decreased and the peak current decreased correspondingly.