Introduction: Simple, fast and accurate objective detection and monitoring of the quality of fill compaction is the goal pursued by engineering construction and supervision, engineering construction and management. As a kind of roadbed strength index, deformation modulus can reflect the characteristics of roadbed. Using the falling ball test technique as the means, under the same rolling conditions, the deformation modulus and compaction degree of the similar filling material subgrade were tested, and the function fitting analysis was carried out to study the deformation modulus and compaction of the filling material. The internal relationship of degree is established, and the relationship model between deformation modulus and compaction degree is established. Finally, the obtained model is used to monitor and detect the quality of the filling project, and compared with the traditional digging and sand filling method to confirm the deformation modulus and pressure. The feasibility of a real relationship model.