The invention discloses a smart water affair management system based on cloud calculation. The smart water affair management system comprises the components of a cloud calculation water affair data center, a water quality monitoring system, an intelligent water discharging system, a sewage processing system, a tap water production scheduling management system, a water affair intelligent security system and a water affair operation system. The smart water affair management system based on cloud calculation is advantageous in that water affair basic data are acquired, stored and mined in a unified manner by the cloud calculation water affair data center, so that the data required by each subsystem in the smart water affair management based on cloud calculation can be acquired through the cloud calculation water affair data center; the cloud calculation water affair data center is used as a data sharing center, thereby preventing information islands among the subsystems; and water affair basic data which are used by each subsystem are supplied by the cloud calculation water affair data center, thereby realizing no requirement for individual data acquisition by each system, and reducing system resource consumption.