Abstract: The seismic isolation performance of substation equipment and structure-equipment interaction have long been critical concerns in engineering practice. In contrast, the research on modular substations with prefabricated equipment cabins remains limited. Seismic isolation shaking table tests were conducted on a prefabricated equipment cabin with a bottom steel frame. The results demonstrate that the isolation bearings effectively reduce the dynamic responses of the cabin itself. However, the equipment acceleration response significantly exceeds that of the cabin, indicating that the seismic isolation measures alone cannot ensure equipment safety. Notably, both the equipment's base connection and the installation location substantially influence the dynamic responses of the cabin and equipment. Thus, a finite element model incorporating equipment and its connections was developed based on experimental data to analyze the effects of base connection stiffness and equipment location on structure-equipment interaction. Findings reveal that the self-tapping screw-connected equipment exhibits rocking motion characteristics. Its acceleration response primarily correlates with cabin base excitation characteristics filtered by isolation and base connection stiffness (equipment frequency). Meanwhile, the displacement response of the equipment, the acceleration of the prefabricated cabin, and the relative displacement of the isolation bearings are predominantly influenced by the base connection stiffness. Under the premise of uniform mass distribution inside the cabin, for an equipment offset, the structure-equipment interaction may lead to twisting of the cabin, whereas a centered arrangement is effective in avoiding this phenomenon.