The multi-point focused explosions of new low-yield earth-penetrating nuclear weapons pose a serious threat to deep underground engineering projects. Addressing the challenge that traditional single-point simulations struggle to replicate the cratering effects of such multi-point synergistic damage, and considering that current explosive testing, while efficient, faces significant limitations hindering normal operations, research innovatively designs and develops a vacuum chamber-based simulation test system for large-yield multi-point focused explosion cratering effects. The core innovation lies in applying similarity theory to convert prototype tests into simulated tests. The vacuum chamber simulation technology enables efficient and rapid simulation of large-yield multi-point explosion cratering effects, with low experimental costs and repeatable results. Based on vacuum chamber explosion simulation theory, the similarity laws governing large-yield multi-point focused explosion cratering were established, defining key parameters such as vacuum chamber pressure and multi-point simulated blast cavity pressure. Synchronization tests verified the simultaneity of multiple explosive sources. Referencing the underground nuclear test, we conducted vacuum chamber simulations for three-point sources under deep burial (4.3 kt, 85 m depth) and shallow burial (5 kt, 20 m depth) scenarios, comparing results with single-point explosion prototype data and empirical formulas. Through synchronization tests and three-point explosive source cratering tests, differences in cratering parameters under varying burial depths and yields were quantitatively analyzed. This revealed a significant advantage in damage range for multi-point sources compared to single-point sources when the total yield is identical. Key results indicate: A vacuum chamber simulation system is successfully developed, relying on a miniature explosive device based on the two-stage gas gun principle and the vacuum chamber. Synchronization tests confirmed good simultaneity among explosive sources using a common detonation control switch; Compared to single-point explosions, multi-point explosions significantly increased crater radius, volume, and free surface projection area, greatly expanding the damage zone; Explosive source burial depth significantly impacts the damage effect.