Abstract: A method that enables rapid determination of lifetime for semiconductor devices based on the study of process-stress accelerated life test is presented, and the theory model is constructed. To demonstrate the application of the method, 3CG120 a kind of mature products, has been used as a sample for test. A process-stress accelerated test was conducted in the temperature range from 175℃ to 345℃ to rapidly extract the data of relationship between temperature and the degradation of sensitive parameters, and the temperature characteristics and degenerating characteristics of sensitive parameters under electrical stress of the specimens were acquired. Then the related reliable parameters, such as activation energy and lifetime were figured out by utilizing the model. The results of experiments are in agreement with literature, which proves that the method is feasible.