The invention relates to a thermal power plant real-time water affair monitoring system and a thermal power plant real-time water affair monitoring method, which solve the problems in the prior art that water affairs cannot be managed in real time, water cannot be used reasonably, pipe network leakage is difficult to discover and the like. The thermal power plant real-time water affair monitoring system provided by the invention comprises a plurality of functional reservoirs, a living water system, a fire fighting water system, an industrial water system and a water affair management system, wherein the living water system, the fire fighting water system and the industrial water system are connected with the corresponding functional reservoirs, water inlet pipes and water outlet pipes of the functional reservoirs, the living water system, the fire fighting water system and the industrial water system are provided with monitoring meters, the monitoring meters are in signal connection with the water affair management system, and water affair real-time monitoring is achieved through the water affair management system. The thermal power plant real-time water affair monitoring system and the thermal power plant real-time water affair monitoring method have the advantages of detecting water affair information in real time, conducting real-time monitoring and calculation by using the water affair management system, calculating power generation water consumption online, discovering unreasonable water utilization phenomenon and water leakage defects of a pipe network, improves water saving facilities, and achieves gradient utilization of water resources.