This paper systematically analyzes the key factors influencing the structural stiffness of emergency evacuation slides. A theoretical formula for the stiffness of the slide’s inflatable tube structure is derived, and a three-dimensional geometric model is established. Using LS-DYNA software, a finite element model is developed to simulate the stress and strain during occupant evacuation, with a focus on evaluating structural stiffness. To validate the numerical simulations, experimental tests were conducted on a fabricated slide prototype, and the results were compared with computational data. The effects of cross-sectional area and operational internal pressure on structural stiffness were investigated. Based on the findings, optimization strategies are proposed: prioritizing structural reinforcement to enhance stiffness, followed by a moderate increase in operational internal pressure. The research outcomes provide valuable insights for the design of various emergency evacuation slides.