In construction projects in areas filled with soil, due to the characteristics of the soil filling material, the bearing capacity and settlement often cannot meet the design requirements, and foundation treatment is required. Taking a construction project in an area with a large height difference as an example, this paper analyzes and discusses the key and difficult points as well as the design ideas of foundation treatment when there is a significant difference in fill thickness. The project has a wide land area, irregular shape, and significant differences in fill thickness. Based on the characteristics of the project, a zoning dynamic compaction method is proposed, and different design methods are adopted according to the differences in fill thickness and design elevation. According to this design concept, the construction process is smooth, and the bearing capacity and deformation meet the design requirements, which can provide useful reference for similar projects.