Discrete element method is widely used in the simulation analysis of the compaction and crushing process of gravel roadbed. In this paper, through the discrete element simulation analysis of gravel subgrade compaction process, the process and law of particle crushing were revealed. The fitting relationship between the settlement of the gravel roadbed and the number of rolling was established to analyze the influence of the paving thickness of the gravel roadbed, the rolling speed, the material stiffness parameters, and the material strength coefficient on the settlement of the gravel roadbed. The research results show that the greater the paving thickness of crushed stone subgrade, the faster the rolling speed, the greater the stiffness coefficient of crushed stone material, and the more rolling times needed to achieve the stable state. The material stiffness coefficient and strength coefficient determine the settlement under the stable state. The discrete element numerical simulation method of the crushed stone subgrade compaction process provides a new method for the study of crushed stone subgrade compaction and crushing. It is a supplement to the field rolling test research of crushed stone subgrade. © 2023 Science Press. All rights reserved.