Abstract: In the structural design of a nuclear safety related plant, it is necessary to consider the impact of heavy container falling. Laying vibration reduction materials (such as autoclaved aerated concrete) at the falling position to form a buffer-layer can effectively reduce the impact caused by falling. Based on the vibration reduction material test and structural scale test, the nonlinear dynamic finite element analysis of the buffer-layer of the plant under impact load was carried out by using ANSYS/LS-DYNA, the constitutive model and its parameters suitable for autoclaved aerated concrete were determined, the key factors affecting the finite element analysis results were explored, and the reduction coefficient considering the influence of stacking was analyzed and defined. The finite element analysis results were in good agreement with the experimental results. Finally, according to the determined constitutive model, parameters and methods, the finite element model of the whole plant was established for impact calculation and analysis, and the vibration reduction design and vibration reduction effect were determined.