This paper establishes a numerical simulation model of the impact resistance of building beam structures by using differential equations. The model fully considers the bolt preload, contact, large nonlinear deformation, and strain rate effect of the building beam structure. The paper establishes and deduces the calculation formulas of the impact force and the lateral displacement of the beam. The study found that under the impact load of the same strength, the failure form of the building beam structure is serious at the assembly point. The local macro/microsimulation results agree with the experimental results. The paper’s results verify the rationality and effectiveness of the numerical method in this paper.