Abstract: Dynamic compaction is one of important methods for ground treatment.But the vibration during dynamic compaction often becomes a problem that restricts the application of dynamic compaction .On the other hand,as an instant impact load with controllable energy, dynamic compaction is a good test insitu for the study of soil dynamics.With the analysis in the field of frequency,computational method for mediumeffecting function and impelling function of dynamic compaction is put forward in this paper.