To correct the 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 novel model algorithm, which is the root test method, and the old model algorithm. The results shows that the old model algorithm can generate errors of more than 13% in the activation energy, and of errors more than 150% in the extrapolated lifetime（Q≤10 eV）,while the novel model algorithm generates errors in less than 1% in activation energy, and errors less than -41% in the extrapolated lifetime.