According to the maintenance cost and long-term benefits of electric equipment, a predictive maintenance decision method based on the service ageis proposed. Firstly, the failure rate is calculated before maintenance based on the equipment status. Secondly, the failure rate after overhauling is predicted based on equipment service age reduction. Thirdly, according to the failure rate, the degree of EENS, the change of LCC and the cost-effectiveness ratio of maintenance are calculated, respectively. Finally, the best maintenance plan is chosen on the basis of the principle of reliability priority, economy priority and cost-effectiveness priority. The results show that the decision-making algorithm of elastic period and elastic state based on the analysis of the age reductionconsidering uncertain factors such as repair efficiency and equipment status of different maintenance strategiesis in line with long-term benefits.