Abstract: To effectively predict the compressive instability load and failure mode of honeycomb sandwich composite structure, the buckling stability of the honeycomb sandwich composite structure under axial compressive loads based on the multi-scale numerical analysis model was studied. The macro-micro multiscale model of the honeycomb sandwich composite structure was established using the improved general cell model and the ABAQUS user-defined subroutine interface. The compressive instability load of the honeycomb sandwich composite structure was predicted and compared with the experimental results. The results show that the numerical model established in this paper can effectively predict the buckling load and failure mode of the honeycomb sandwich composite structure under compression load. The predicted first-order buckling load of the structure is 128.12 kN, which have an error of 4.58% compared with the experimental result. The failure modes of the sandwich structure are first buckling instability and then rapid failure.