The “7.20” catastrophic rainstorm and flood in Zhengzhou was a typical compound chain disaster. Extreme heavy rain caused river floods，mountain torrents，urban waterlogging，subway tunnel flood，and underground space flood. Meanwhile，the rainstorm also caused a few secondary and derived events，such as the aluminum alloy plant explosion，large area blackout incident，etc. With the joint efforts of the local government，the army and the armed police，the dangerous situation of the reservoirs was successfully handled. All departments and rescue forces made every effort to carry out rescue work after the occurrence of water logging hazard in Metro line 5，Jingguang expressway north tunnel，and several hospitals，etc. The problems exposed in this disaster response process bring us three enlightenments. Firstly，we should strengthen bottom-line thinking and make full emergency preparedness. Secondly，we should optimize the unified leadership system for major disasters and improve the emergency command system. Thirdly，we should improve emergency management capability and mechanism.