Abstract: To study the dynamic response of contact force and damage condition of composite sandwich structures with thin facesheets subject to impact load, specimens of different facesheet thicknesses were tested via dropping weight method at various levels of impact energy using two impactors of different mass. The damage of specimen after impact was measured. The results reveal that when the impact energy is relatively low, the maximum contact force is low and increases with the increase of impact energy, and it will be constant after it reaches the threshold value. The dent in the facesheet and slight delamination around the impact center are the major failure modes at low impact energy, and fiber fracture and penetration will emerge as the impact energy increases. The diameter of delamination area is about 1.2 times of the impactor when the facesheet is un-penetrated with impactor rebound, and in this case there is no plateau on the declining stage of contact force-time curve. While in the penetrated cases, the impactor does not rebound and the diameter of delamination area is about 1.8 times of the impactor, in this case, there is plateau on the declining stage of contact force-time curve. Besides, the bigger mass impactor will lead to longer contact duration and bigger dent depth under the same impact energy after the maximum contact force reaches the threshold value.