To provide theoretical basis for metal honeycombs used as buffering and crashworthy structures, the effect of the cell length and foil thickness on compressive properties of metal honeycombs is investigated by numerical simulation. Numerical results are well consistent with the corresponding experimental results. The numerical results show that metal honeycombs have cyclic buckling when loaded in out-of-plane direction. The thicker the foil is or the shorter the cell length is, the higher the plastic collapse stress is and the plastic collapse stress is much sensitive when cell length is short. The numerical simulation used in this paper can well predict the crush behavior. Single and doubled foil portions of cell walls are also accounted in the FE model. The results demonstrate that the method is effective which can be used in optimization design of buffers.