Emergency　management　research　is　used　to　deal　with　the　increasing　number　of　extreme　weather　threats　in　urban　areas.　This　paper　uses　causal　analysis　based　on　systems　theory　(CAST)　to　review　the　subway　water　ingress　accident　and　the　government＇s　emergency　management　actions　in　Zhengzhou,　Henan　Province,　during　the　heavy　rainstorm　disaster　on　20　July　2021.　The　aims　of　this　article　are　to　establish　safety　control　structures　at　both　the　enterprise　level　and　the　government　level,　and　to　systematically　analyze　the　problems　in　emergency　management　in　Zhengzhou　City.　Our　analysis　found　that　the　construction　of　disaster　prevention　facilities　restricted　emergency　management.　Therefore,　we　suggest　that　enterprises　and　governments　not　only　pay　attention　to　emergency　management,　but　also　to　the　construction　of　disaster　prevention　facilities.　This　article　also　points　out　that　the　system　of　chief　executive　responsibility　that　is　implemented　in　China　is　becoming　a　double-edged　sword　in　emergency　management.　Our　study　makes　recommendations　for　enhancing　the　capacities　of　emergency　management,　points　out　the　shortcomings　of　the　existing　emergency　management　structure,　and　provides　knowledge　gained　for　future　emergency　management　research.