Abstract: The polythionine modified carbon paste electrode (PTH/CPE) was prepared, and the polymer film was characterized by SEM and the electrochemical behavior of enoxacin at this modified electrode was studied by cyclic voltammetry. Significant electrocatalytic action on the reaction of enoxacin at modified electrode was observed, giving an oxidation peak in PBS of pH 4.94. Based on this fact, a method of differential pulse voltammetry was proposed for the determination of enoxacin. Linear relationship between values of oxidation peak current and concentration of enoxacin was obtained in the range from 1.0×10-5 to 2.0×10-4mol·L-1, with detection limit (3S/N) of 4.0×10-6mol·L-1.