Abstract: In recent years, the expressway network has been gradually improved, and the implementation of expressway projects of various sizes makes more convenient and created great economic benefits. However,the line span of expressway projects is large, which often spans many areas. Subgrade fi lling serves as the key construction process in the subgrade construction. Because of the strict technical standards and topographic and geological restrictions, the technical problems in the subgrade filling are intensified, and the subgrade strength and stability are difficult to meet the construction requirements. Based on this, this paper takes Guanglian expressway as the research object, analyzes the relevant technology of subgrade fi lling in detail, and puts forward the relevant key points of quality control, which has a certain guiding value for the same type of construction operation.