When building groups are subjected to earthquakes, the potential hazard of exterior falling debris poses a significant risk of causing severe injuries and fatalities. In this study, an integrated simulation method of the large-scale earthquake-induced exterior falling debris for building groups is proposed, which includes modeling, calculation, and visualization. Firstly, a modeling algorithm is established for falling debris models of building groups. This algorithm employs the Octree algorithm to support the transformation of the three-dimensional (3D) building surface model into falling debris models. Subsequently, the generated falling debris models are aggregated using a density clustering algorithm, and their motion is efficiently calculated based on the physics engine and time history analysis. Finally, a cooperative visualization algorithm is developed to effectively present a 3D scene that incorporates both structural displacement and the motion of falling debris in building groups. The actual distribution of exterior falling debris during the earthquake in Turkey validates the proposed simulation method, which is then integrally applied to the Beijing central business district. This integrated simulation method has the capability to provide a large-scale 3D scene of falling debris for the virtual safety drills of earthquake evacuation and rescue within urban building groups.