Abstract: In order to prepare oxygen-containing heterocyclic flavor and evaluate its flavoring effect in cigarette, a flue-cured tobacco sample was pyrolyzed by a furnace-type pyrolyzer and the particulate matters were collected by Cambridge filter pads under the heating temperature of 200 ℃, 250 ℃ and 300 ℃ with collection times of 5, 10 and 20 min. The effects of the pyrolysis conditions on the formation of oxygen-containing heterocyclic compounds were investigated by GC/MS method. Pyrolysis products were separated by using C₁₈ chromatographic column and eluted with different concentrations of ethanol. The optimal eluate was determined by TOF/MS analysis and olfactory evaluation to determine flavoring effect. The results indicated that: 1) Under the optimal pyrolysis condition of temperature 250 ℃ and collection time 10 min, the yields of oxygen-containing heterocyclic compounds (such as furfural, 5-methylfurfural and 2, 3-dihydro-3, 5-dihydroxy-6-methyl-4H-pyran-4-one), which were known to significantly enhance the burnt-sweetness scent of cigarette smoke, were the highest. 2) Comparing with the eluates of 20% and 30% ethanol solutions, those of water, 5% and 10% ethanol solutions contained more oxygen-containing heterocyclic compounds with higher concentrations and clear burnt-sweetness scent. 3) After flavoring with the 10% ethanol eluate of pyrolysis product obtained under the optimal pyrolysis conditions, the cigarette smoke featured an outstanding burnt-sweetness scent; the smoothness, sweetness, aroma, and abundance of cigarette smoke were promoted, and irritation and dryness of the smoke were reduced, and offensive odor was masked.