The stability of rock cavern foundations has long been a fundamental research topic in geotechnical engineering. It is critical for various construction projects, including karst mountain foundations, civil defense tunnel shelters, and urban infrastructure such as highways, railways, and tunnels. While the stability of the cavern itself has been extensively studied and is relatively mature, research on rock cavern foundation stability is relatively nascent, particularly concerning foundations influenced by steep inclined structural surfaces. Based on engineering examples, the study identifies existing problems in current analyses of cavern foundation stability. A calculation method for the stability of rock cavern foundations affected by steep inclined structural surfaces is established to analyze their influencing factors and patterns. The research proposes an analysis method for cavern foundation stability under the influence of steep inclined structures. Different foundation forms are analyzed for their stability, and the results are validated using the 3DEC discrete element calculation software. The findings offer practical guidance for the design and development of cavern foundations.