Abstract: Ten PAHs generated by pyrolysis of flue-cured,burley and oriental tobacco samples in nitrogen at different temperatures were determined by pyrolysis-GC/MS.The results showed that 1) when the pyrolytic temperature was below 550℃,no PAHs was detected.When the temperature was at 600℃ or 650℃,fluorene,phenanthrene,anthracene,fluoranthene and pyrene were detected.At 700℃,benzoaanthracene and chrysene emerged in pyrolysates of flue-cured and oriental tobacco samples,while not in pyrolysate of burley tobacco sample.At 750℃,benzokfluoranthene,benzoepyrene and benzoapyrene emerged in flue-cured and burley tobacco pyrolysates,while not in oriental tobacco pyrolysate.From 800℃ to 900℃,those mentioned PAHs were detected in all samples.2) PAHs yield increased with the increase of pyrolytic temperature from 600℃ to 900℃,however,it differed to a certain extent between different tobacco samples at same pyrolytic temperature.Over 800℃,the yield of most PAHs was highest in the pyrolysate of oriental tobacco and lowest in that of burley tobacco,though it was not below 750℃.With the increase of pyrolytic temperature,the PAHs yield of oriental tobacco sample increased more rapidly than did the samples of other two tobaccos.