Abstract: AIM To study the mechanism of a polarographic catalytic wave of hesperidin in the presence of hydrogen peroxide, and to propose a new catalytic wave method for the determination of hesperidin. METHODS Linear-potential scan polarography, cyclic voltammetry and DC polarography were used in this work. RESULTS In 0.12 mol·L^-1 HAc-0.40 mol·L^-1 NaAc (pH 5.3) supporting electrolyte, the carbonyl group C==O of hesperidin at the C-4 position yielded two reduction waves. The carbonyl group C==O firstly undergoes a 1 e, 1H⁺ reduction to form an intermediate free radical, producing the first reduction wave with peak potential -1.35 V (vs SCE). Further reduction of the radical was simultaneous with its dimerization. A part of the radical was further reduced, producing the second reduction wave with peak potential -1.70 V (vs SCE). Other part of the free radical was dimerized. The dimer could be oxidized at -1.17 V (vs SCE). When oxidant H2O2 was present, both the further reduction and dimerization were interrupted, and a polarographic catalytic wave was produced because H2O2 oxidized the intermediate free radical to regenerate the original C==O group. Based on the polarographic catalytic wave, a new method for the determination of hesperidin was proposed. 0.12 mol·L^-1 HAc-0.40 mol·L^-1 NaAc (pH 5.3)-1.0×10^-2 mol·L^-1 H2O2 solution was chosen as supporting electrolyte. The first-order derivative technique was used to eliminate the higher background current from H2O2 reduction and to well separate the catalytic wave from H2O2 reduction wave. The first-order derivative peak current of the catalytic wave is proportional to hesperidin concentration in the range of 1.0×10^-7 -1.8×10^-6 mol·L^-1 with correlation coefficient γ=0.9954. The limit of detection was 8.0×10^-8 mol·L^-1. The sensitivity of the catalytic wave was higher by one order of magnitude than other electrochemical methods based on reduction wave previously reported. CONCLUSION The catalytic wave method has higher sensitivity and can be used for pharmaceutical analysis.