In order to predict the life of electronic equipments with high reliability and long life, based on Arrhenius model and their linear degradation path, a time equivalence method was proposed for the step-stress accelerated degradation test under the temperature stress. The calculation formulae were also induced. The step-stress accelerated life tests of one type of integrated operational amplifier were carried out, and the data were processed with this method under four different temperatures. The results show that the pseudo lifetime of the sample follows the lognormal distribution, and the accelerated model agrees with Arrhenius equation. Then, the median life could be evaluated, and the life prediction is realized.