Abstract: In order to investigate important neutral aroma components in mainstream cigarette smoke that play decisive roles in demonstrating the aroma style of cigarettes, the functional thresholds of 32 key neutral aroma components were sensorilly evaluated by the method of functional thresholds for tobacco flavors, and their releases in mainstream cigarette smoke were determined by GC-MS. The activity thresholds of the 32 components were obtained and analyzed. The results showed that:1) The functional thresholds of the 32 components ranged from 7.04×10^-14 to 6.76×10^-7 μg·cig^-1; those of ethyl valerate and β-damascone were the lowest, while those of six neutral components, such as methyl 2-furoate, were higher. The maximum difference of functional thresholds among the 32 components covered about seven orders of magnitude. 2) The total content of 32 neutral components in mainstream cigarette smoke was 11.320 μg·cig^-1. The content of 5-methylfurfural was the highest (5.881 μg·cig^-1), which accounted for 52.0% of the total content. The contents of β-damascenone and phenethyl alcohol were relatively higher, and the sum of their contents accounted for 14.5% of the total content. 3) The activity thresholds of the 32 components ranged from 2.45×10⁴ to 2.77×10¹², which was 6.38×10¹² in total. The sum of activity thresholds of seven components, such as ethyl valerate, accounted for 96.5% of the total activity thresholds, which indicates that the above seven neutral components played decisive roles in demonstrating the aroma style of cigarette.