In this paper, the in-situ dynamic compaction tests with different values of single-drop-compaction energy are performed on a liquefiable ground encountered in highway engineering practice. Excess pore pressure, total surface settlement and lateral deformation under dynamic compaction impact are measured and analyzed at different conditions, such as single drop-compaction-energy, drop numbers, depth of soil layer etc. The standard penetration test (SPT) is used for investigating the compaction effectiveness. The investigation results indicate dynamic compaction technique is an effective way for improving liquefiable ground in highway engineering practice. Relatively small single-drop-compaction energy and relatively more drop numbers should be adopted for improving natural sedimentary liquefiable ground with dynamic compaction. The in-situ dynamic compaction tests show that the effective effect range by dynamic compaction impact depends on the single-drop-compaction energy. It is also found that the measured maximum lateral deformation has a good linear relationship with the total vertical surface settlement
