Abstract: In 0.04 mol/L Brittion-Robinson buffer solution(pH=4.60), the electrochemical behavior of rhein at a glassy carbon electrode has been studied by cyclic voltammetry, linear sweep and pulse voltammetry. The experimental results indicated that the number of electron involved in this electrochemical reation was 2, and the electrode transfer coefficient was 1.06. Meanwhile, the electrochemical reaction mechanism of this system has also been discussed. The linear response range for Rhein was 4.0×10^-7 mol/L～1.0×10^-5 mol/L with a detection limit of 3.9×10^-8 mol/L (D=3σ/K). The method has been used for the determination of Rhein in Rhubarb and Sodium Bicarbonate Tablets and in serum of rabbit.