In modern military operations and emergency response scenarios, the structural integrity and protective capacity of square cabin are crucial for ensuring the safety of personnel and equipment. The dynamic response of the square cabin under explosion loading is substantially affected by explosive yield and standoff distance due to the significant energy attenuation characteristics during propagation in air. This study employs the Load Blast Enhanced (LBE) method in LS-DYNA to conduct numerical simulations of square cabin under TNT equivalents of 1.04 kg, 2.04 kg, and 3.04 kg. Stress contour of the surface and frame structure were extracted for quantitative analysis. The results demonstrate that plastic deformation and fracture extent of the square cabin skins and frame increase significantly with higher explosive equivalent and reduced standoff distances. The simulated stress distribution patterns show strong consistency with experimental data, validating the reliability of the algorithm in explosive load-structure coupling analysis. These findings provide theoretical support for optimizing blast-resistant designs and evaluating the protective performance of shelter structures.