This paper proposes a sand-filled aluminium honeycomb sandwich structure for protective structures. Based on the results of the theoretical analysis, the author conducted a drop weight impact experiment was conducted on several specimens, seeking to obtain the data on impact load, impactor displacement and structure deflection, and observe damage modes of structures at different impact energies. Then, the LS-DYNA was employed to validate the simulation model. The experiment results demonstrate that the strength and stiffness of the structures were improved by sand-filling under the impact of low energy level, especially for the structures with softer honeycomb core. With the same mass, honeycomb core with smaller cell size and lower height is preferable at low energy level. Localized structural deflection and damaged area were also observed under impact of high-energy level when the core height reached a fixed value. The model of numerical simulation was validated with the experimental results, which can be used in further research.