Abstract: In a base solution of Tris-HCl buffer of pH 7.5,a sensitive oxidation peak of vanillin was observed at the peak potential of +0.54 V,as shown in the cyclic voltammogram.It was found that linear relationship between values of peak current (Ip) and concentration of vanillin was kept in the range from 3.286 ×10-6-3.944×10-4mol·L-1.Detection limit (3S/N) of the method found was 1.643×10-6mol·L-1.Base on these facts,a method of voltammetric determination of vanillin was proposed,and applied to the analysis of chocolate for its vanillin content.Different amounts of standard vanillin were added to the chocolate sample and analyzed by the proposed method to test for its recovery,the result of average recovery obtained was 99.6%.As shown by the result of electrochemical study,the electrochemical behavior of vanillin at the glassy carbon electrode (GCE) was an adsorptive and irreversible electrode process.