The invention belongs to the energy source circulating reuse field and discloses a boiler flue gas reuse method, which integrates the boiler flue gas use and the clean pulping production improved wood, namely using the fume of the boiler and the cogeneration boiler, through the electro dedust to remove the dust in the fume, as one of the hot wind source of the centrifugal spray drying means to produce the improved wood, realizes the utilization of the fume remaining heat. Meanwhile in the spray drying process, the sulfur dioxide, the nitric oxides in the fume are adsorbed and used in the spray drying means of the improved wood, which advances the quality of the improved wood, purifies the boiler off gas, to make the boiler fume standard discharge develop waste cyclic utilization means, and reduce the pulping paper making and the off gas contamination.