The kinetics of hydrolysis of olive oil，peanut oil，soybean oil，safflower oil in near-critical water was systematically determined in the temperature range from 170℃ to 240℃ and at pressure of 10 MPa. From the results，it could be seen that the vegetable oil hydrolysis in near-critical water was a typical self-catalyzed reaction. With a second-order kinetics equation，the activation energies evaluated were 41. 8 kJ·mol-1 for olive oil，37. 3 kJ·mol-1 for peanut oil，37. 7 kJ·mol-1 for soybean oil， 31. 2 kJ·mol-1 for safflower oil respectively. The activation energies of different vegetable oils had a close relationship with their iodine values. With increasing iodine value，the activation energy of vegetable oil hydrolysis in near-critical water decreased.