Abstract: In order to study the influence of impulse loads on the aging of oil paper insulation of traction transformer, in this paper, the accelerated thermal aging tests of oil-paper insulation under impulse loads were designed considering 3 factors such as the load rate, lasting time, and time interval of impulse loads. The change law of the degree of polymerization and tensile strength of the paper insulation during the aging process of the samples with different impulse load conditions were analyzed. The thermal aging data of oil-paper insulation under impulse loads were analyzed by using the Ekenstam aging dynamic model and entropy method, meanwhile, the impact of impulse loads on the operating life of oil-paper insulation was analyzed by converting the test results to the operating life at the rated load. The results show that the impulse load has an obvious effect on the aging rate and service life of oil-paper insulation and the impact strength is similar. Then, the aging rate, rate parameters and equivalent temperature in the Emsley model all have positive relations with the load rate and lasting time, and have negative relations with time interval. As the load rate and lasting time increase, the operating life of the oil-paper insulation decreases, and the greater the time interval, the longer the operating life. However, the relationship between service life and impulse load needs further study.