Abstract: The reinforced concrete slab-buffer layer combination structure is often used for the prevention and control of rockfall disasters. In order to study the dynamic response of such structures under the action of falling rocks, based on ABAQUS finite element method, the impact force model, buffer effect and reinforced concrete slab damage were studied numerically with buffer layer thickness and falling rock impact velocity as parameters. The results show that during the impact process, the nominal impact force between the rockfall and buffer layer surface is much larger than the real impact force. When the buffer layer is 0.6m and the impact velocity are 20m/s, 15m/s, 10m/s respectively, the impact attenuation rates are 42.0%, 42.0%, and 40.0%. Compared with the current typical impact calculation model, it found that the impact force was positively correlated with the impact velocity at different impact speeds, which was in agreement with the Japanese formula and the tunnel specification. The displacement analysis of the concrete slab showed that under a certain buffer layer thickness, as the impact velocity increased, the permanent deformation increased, and the rebound amount accounted for a small proportion of the total deformation; the maximum damage range had no relation with thickness of the buffer layer. In the case of same thickness of the buffer layers, the damage cone angle formed by the corresponding plate damaged position and the outer edge of the damage was between 30° and 45°. The impact velocity largely affected the extent of damage and the extent of damage. The conclusions of this paper have important guiding significance for the design of rockfall protection structure.