Air-supported　membrane　structures　are　widely　used　in　stadiums,　malls,　and　museums.　The　stiffness　and　shape　of　such　structures　are　dependent　on　the　pressure　difference　between　the　indoor　and　outdoor　environments.　As　the　leakage　of　indoor　air　may　lead　to　the　collapse　of　the　structure,　it　is　necessary　to　study　the　deflation　deformation　process,　including　the　properties　that　can　cause　air-supported　membrane　structures　to　collapse.　In　this　study,　a　rectangular　air-supported　membrane　structure　is　fabricated　using　a　PVC-coated　polyester　fabric　membrane　with　dimensions　of　38　m　x　20　m　x　7　m,　and　a　leakage　experiment　is　performed.　The　relationship　between　the　initial　leakage　area　and　the　pressure　difference　is　obtained,　and　a　new　algorithm　to　determine　the　equivalent　initial　leakage　rate　is　proposed.　A　collapse　test　is　then　conducted,　with　results　illustrating　that　there　are　two　distinct　phases　of　collapse.　There　is　a　quick　drop　in　the　pressure　difference　in　the　first　phase,　whereas　the　pressure　difference　declines　rather　slowly　in　the　second　phase.　Computational　formulae　for　collapse　and　escape　times　are　established,　and　finally,　a　quasi-equilibrium　status-based　algorithm　to　determine　the　collapse　time　of　air-supported　structures　is　proposed.　Using　the　new　algorithm,　several　main　parameters　that　influence　the　collapse　of　air-supported　structures　are　studied,　including　the　cables,　initial　pressure,　and　leakage　area.　Results　show　that　the　initial　pressure　has　a　minimal　effect　on　the　collapse　of　structures,　while　excessive　cables　accelerate　the　process　of　collapse.