The invention relates to a method for separating and preparing key acid 
flavor components in cigarette mainstream 
smoke. The method takes the acidic components in the cigarette mainstream 
smoke as a 
raw material, the acidic components in the cigarette mainstream 
smoke are subjected to 
linear gradient elution through medium-pressure prepared liquid 
chromatography, and the same volumes of eluted fractions are sequentially collected; and the 
gas chromatography-
mass spectrometry is adopted to analyze all the eluted fractions, and with the help of sense smoke panel test, three key acid 
flavor components F4, F5 and F6 are screened finally. The result shows that the fraction F4 has obvious functions of improving smoke 
impact, increasing smoke concentration and reducing stimulation; the fraction F5 has obvious functions of improving 
aroma quality and smoke 
impact and increasing smoke concentration as well as the functions of increasing 
aroma quantity, covering miscellaneous gases and improving permeability; and the fraction F6 has the obvious functions of improving 
aroma quality, increasing aroma quantity, improving permeability and smoke 
impact and increasing smoke concentration as well as the function of improving residual taste.