Abstract: The out-plane shear behavior and mechanical properties of aluminum honeycomb sandwich panel were studied by experiment and numerical simulation. The failure modes were discussed, and the typical load-displacement curves were obtained. The effects of face sheet thickness, cell size and core height on the pick load and energy absorption capacity of the sandwich panel were analyzed. The results show that the out-plane shear failure process of aluminum honeycomb sandwich panel goes through four stages: Elastic-plastic deformation, upper sheet damage failure, core layer density and lower sheet damage failure, and presents two failure modes: Integral failure and phased failure. The type of failure mode is mainly determined by the relative relationship between face sheet thickness and cell size. Increasing face sheet thickness or cell size will transform the failure mode from integral failure to phased failure, and the energy absorption capacity of phased failure mode is higher than integral failure mode. The shear strength and energy absorption capacity increase with the increase of face sheet thickness, but decrease with the increase of cell size. The shear strength is slightly affected by the core height, but the energy absorption capacity of sandwich panel increases with the increase of core height. The simulation results are in good agreement with the experimental results, which fully verifies the reliability of the finite element model.