The work aims to explore the influence of thickness upon its out-of-plane impact properties by taking the hexagonal honeycomb paperboard as a study object. The relations among contact force, maximum contact force, maximum displacement, maximum strain, absorption energy and impact energy per unit thickness were analyzed through the dynamic impact tests. On the basis of that, the out-of-plane impact properties of four honeycomb paperboards at the thicknesses of 30, 40, 50 and 60 mm were studied. The contact force gradually decreased and the contact duration gradually increased with the increase in the honeycomb paperboard thickness for the given impact energy. When the impact energy per unit thickness was specified, the thickness was directly proportional to the maximum displacement and absorption energy; while the thickness was inversely proportional to the contact force, maximum contact force and maximum strain. For the honeycomb paperboard of any thickness, the maximum contact force, maximum displacement, maximum strain and absorption energy would linearly increase as the impact energy per unit thickness increased. For the same impact energy, the absorption energy of honeycomb paperboard of different thicknesses is almost the same. As a result, the absorption energy capacity of honeycomb paperboard, only depending upon the magnitude of impact energy, has nothing to do with its thickness.