The electrochemical behavior of acyclovir on the boron-doped diamond（BDD）electrode and its interaction with DNA in 0.10 mol/L phosphate buffer solution（pH 7.4） were studied by cyclic voltammetry and differential pulse voltammetric method-Compared with that on glassy carbon electrode,an oxidation peak of acyclovir at 1.17 V with lower background current and higher peak current was observed on the BDD electrode.The electrochemical oxidation mechanism of acyclovir on the BDD electrode was investigated by the relationships of the oxidation peak potential with the scan rate and pH value,and 2-electron-transfer and 2-proton-participation in the oxidation process of acyclovir were found.The study of interaction between different proportions of acyclovir and DNA indicated that acyclovir interacted DNA based on inset mode with binding site of 1.07 and binding constant of 4.47×106.The above results were further verified by the study of the interactions of acyclovir with single-stranded DNA and double-stranded DNA,respectively.