In order to solve the deficiency of the current evaluation index and realize the optimization of anti-rutting of asphalt mixtures. Based on the urban road repair project, this paper adopted the discrete element and plastic activation energy evaluation method to optimize the anti-rutting performance of the test road from gradation design, in which, the theory of plastic activation energy was emphatically introduced, and the test and calculation method of plastic activation energy index were given. During the research process, the optimized gradation was first determined through the virtual creep test of discrete element, then the indoor creep tests were carried out on the asphalt mixture with the optimized and the original gradation, including eight groups of tests under the conditions of immersion and non immersion, 20℃ and 40℃, damage (300kPa) and non-damage (25kPa) respectively. At the same time, the plastic activation energy index was calculated based on the plastic activation energy theory, and the results showed that the optimal gradation has higher plastic activation energy. Finally, the asphalt mixture with the original gradation and the optimized gradation were used to build the test road, and the settlements were monitored. The results showed that the rutting of the road with the optimized gradation is smaller, which is consistent with the evaluation results of the plastic activation energy index.