Dynamic compaction is currently regarded as one of the quick but cost-effective method for soil densification to resist the potential of soil liquefaction during earthquake. Most practices and studies reveal the depth of densification is mainly limited by the compaction energy without considering the effect of water table. In this experimental study, the impact performances under both presence and absence of water level without changing the compaction energy were presented. The Single-point Impact Test is developed to perform a series of tests on soils under different water levels and drained conditions. Meanwhile, an automatic cone penetrometer is also developed to evaluate the effectiveness. The boundary effect of soil container used in the test is also discussed. The impact-induced pore pressures and dissipation periods are measured and compared with a field measurement. The relationship between the effective dynamic stresses and corresponding cone resistances in soils is highlighted. The performance of dynamic impacts is evaluated by a term of improvement ratio.