As a porous sandwich plate system, the honeycomb paperboard is widely used in cushioning packaging of products due to its energy-absorbing properties. The drop impact on a honeycomb paperboard with cell sizes of 4 mm, 6 mm, and 8 mm was simulated and experimented to investigate the paperboard’s energy absorption and deformation modes. The peak impact force of the impactor with velocity 5.47 m s⁻¹, the dent depth of the honeycomb paperboard, and the absorbed energy were obtained. The peak forces corresponding to the core layer cell sizes of 4 mm, 6 mm, and 8 mm were 141.2 N, 108.7 N, and 97.7 N, and the absorbed energy values were 76%, 83%, and 84%, respectively. The model of honeycomb paperboard under drop impact was established. The plastic deformation and force distribution showed good agreement with experimental results, which verified the accuracy of the model. The results are expected to provide a reference for the lightweight structure and protective design of the honeycomb paperboard.