Bridge pier covered by buffer structure in mountain areas can effectively reduce the impact of debris flow, and protect itself. As an energy dissipation buffer material, the aluminum foam combined with steel plate was introduced to protect the bridge pier from the impact of debris flow. The mechanical properties of five different structural forms of sandwich panels were analyzed by static load test. The results show: the aluminum foam sandwich structure has a broad and flat range of energy buffer and dissipation which can absorb a large amount of impact energy; the double-layer aluminum foam sandwich structure is the best structural form by comparing the energy dissipation performance among the five different structural forms of sandwich panels. On this basis, an optimized structure was applied to the bridge pier across the debris flow, and the effect of engineering application is remarkable.