The work aims to study the influences of impact velocity and configuration parameters on the out-of-plane plateau stress of honeycombs filled with mix of squares and triangles. A reliable finite element model was established based on array of cells using ANSYS/LS-DYNA for out-of-plane impact analysis. The theoretical formula of quasi-static plateau stress was derived based on the simplified super folded element theory for honeycombs filled with mix of squares and triangles. The theoretical results were consistent with the simulated ones, which verified the reliability of theoretical formula. For honeycombs with different ratios of cell wall thickness to edge length, simulations were carried out under different out-of-plane impact velocities. The corresponding deformation modes, contact force-displacement curves and plateau stresses were obtained through the LS-PrePost software, and presented and analyzed in the form of tables and diagrams. At different impact velocities, the honeycomb with fixed configuration parameters showed three different out-of-plane impact deformation modes:LS mode, MS mode and HS mode, and the critical velocities from LS mode to MS mode and then to HS mode were about 20 m/s and 150 m/s respectively. The influence of the ratio of cell wall thickness to edge length on the deformation mode could be ignored. The dynamic plateau stress of honeycombs filled with mix of squares and triangles increases with the increase of the impact velocity (or ratio of cell wall thickness to edge length), and the growth rate increases continuously. When other parameters are fixed, the relation between the dynamic plateau stress and the impact velocity of the honeycomb in LS mode and MS mode is quadratic, and the relation between the dynamic plateau stress and the square of the impact velocity in HS mode is linear. The relation between the dynamic plateau stress and the ratio of cell wall thickness to edge length is a power function. From the simulation results, the empirical formulas of its dynamic plateau stress are derived.