To correct error in theoretical model of process-stress accelerated test, a new calculation method is proposed. The new method, based on computer-aided calculation, can significantly reduce the error of the model. Theoretical data is calculated using both the new model algorithm, which is the root test method, and the old model algorithm. The results show that the old model algorithm can generate error more than 13% in the activation energy and error more than 150% in the extrapolated lifetime (Q≤1.0eV), while the new model algorithm generates error less than 1% in activation energy, and error less than 4.1% in the extrapolated lifetime.