Abstract: A method was developed, coupling the discrete element method (DEM) and finite difference method (FDM), and used to perform prediction analysis on the impact of bodies resulting from landslides on the retaining wall of the Longdongzi Tunnel structure. Three kinds of structure models were constructed and simulated numerically. In the numerical models, the collapse bodies were simulated by the assemblies of particles, the retaining wall was simulated by a rigid wall, particles, and solid elements in FLAC. The simulation results from the coupled computational method were used to analyze the dynamic response and deformation of the retaining wall in the various models. By comparing the numerical results, the optimal structural model and computational parameters were chosen, which provides theoretical guidance for effective collapse prevention for protective structure design.