The reservoir space of fracture-cavity reservoirs is primarily composed of interconnected caves and fractures. Caves are utilized as the dominant hydrocarbon storage spaces, while independent caves are linked by fractures to establish an integrated hydrocarbon storage system. During petroleum production, cave collapse and the closure of principal fracture flow pathways are commonly triggered by reservoir pressure depletion, resulting in significant reductions in well productivity and ultimate hydrocarbon recovery. In this work, the structural stability of caves within fracture-cavity reservoirs under fluid-solid coupling actions was systematically explored. True three-dimensional physical model experiments were conducted based on the geological background of the Tahe Oilfield in Xinjiang. The entire collapse process of fracture-cavity reservoirs was precisely simulated. The evolution laws of displacement and stress fields during cave failure and the interaction mechanisms between caves and fractures were thoroughly identified. The intrinsic collapse mechanisms of fracture-cavity reservoirs were ultimately elucidated, and key technical support was offered for the prevention and control of reservoir destabilization risks in oilfield development.