Abstract: The changes of the density and permeability of the Land-based gravel in the dynamic compaction researched by the bulk density test and injection test at the scene,discussed the soil structure which effected by the dynamic compaction. The results show that: dynamic compaction can improve the structure of the gravel soil, especially superficial zone, the deeper, the more unconspicuous. Under the Dynamic compaction, the changes of the soil structure is due to the grain filling in the above 3 m,and 3m the following is due to the compression of soil pore.