Abstract: A certain ultra-high voltage substation is located in the mountainous area of Zhejiang Province, with a fluctuating terrain that requires half excavation and half filling. The surface layer is composed of silty clay, and the underlying layer is completely weathered, strongly weathered, and moderately weathered sandstone. The first trial compaction failed due to excessive compaction capacity and inability to lift the hammer. Summarize the lessons of failure and adopt a second trial compaction plan with small compactors capable of multiple passes. Through various trial compaction tests, the bearing capacity, deformation modulus, and compactness of the treated foundation meet the design requirements. This trial compaction laid the foundation for determining the parameters of the engineering dynamic compaction, and ultimately achieved satisfactory results. After years of settlement observation, the settlement of the site after construction was relatively small.