<p>LNG membrane tanks feature a composite structure, with the 304 L stainless steel membrane serving as a critical component. Ensuring membrane reliability and safety under extreme low-temperature conditions requires systematic investigation of their mechanical properties. This study presents numerical simulations and experimental verification of LNG membrane mechanical properties. Through quasistatic tensile tests, finite element simulations, and actual model tests, the research established stress-strain curves of 304 L stainless steel at various temperatures and examined the mechanical behavior and deformation characteristics of LNG membranes at low temperatures. The findings demonstrate that 304 L stainless steel exhibits significantly increased tensile strength at low temperatures, while showing decreased elongation. Under low-temperature conditions, small corrugations display reduced extensibility but enhanced tensile strength, whereas large corrugations demonstrate opposite characteristics. Furthermore, this study elucidates the permanent deformation patterns of LNG membranes under low-temperature and high-load conditions. The maximum displacement of membranes increases with load in both large and small corrugation areas, though their recovery capability improves at low temperatures, with varying tensile and elongation properties in different directions. Based on these results, the study proposes a calibration standard for LNG membranes, providing theoretical foundations for practical applications.</p>