Abstract: To mitigate energy loss and emissions from high-temperature flue gas in thermal power plants, this study develops a multi-stage recovery system for a 300MW coal-fired unit. Integrating spray cooling, direct contact exchangers, heat pumps, and gas boilers, the system efficiently recovers sensible and latent heat for district heating. Without disrupting main operations, the retrofit lowers flue gas temperature to 30°C, boosts efficiency above 80%, and cuts annual coal use by 40,000 tons, offering a replicable path for green energy transition in the thermal power industry.