The low-temperature flue gas waste heat recovery system at the tail of the fuel boiler in the power plant can reduce the exhaust temperature of the boiler from around 150 ℃~125 ℃ by 40~30 ℃ before entering the dust collector. While increasing dust removal efficiency, the waste heat is utilized to increase the power generation of the steam turbine, achieving coal savings of 1~4g/kWh and improving unit efficiency by 0.2~1.2%.