Abstract: The epoxidation of soybean oil with dilute aqueous solution of hydrogen peroxide and acetic acid in the presence of cation exchanger resin catalyst was studied. The effect of reaction parameters, such as reaction temperature, the addition of mineral acid additives, the amount of H_2O_2 aqueous solution and exchanger resin catalyst was discussed. The results showed that the epoxide numbers of the epoxidation product reach more than 6.30 within 20 h, when the reaction conditions are appropriate.