Abstract: Using cigarettes with an activated carbon filter or a regular cellulose acetate filter as the research objects, the retention behavior of the activated carbon filter on alkaloids in mainstream cigarette smoke were comparatively analyzed. The optimal extraction conditions for alkaloids in activated carbon filter were determined by single-factor and orthogonal experiments, and the alkaloid contents in cigarette butts and mainstream smoke were determined to analyze the effects of the activated carbon filter on the alkaloid retention. The results showed that: 1) The optimal extraction conditions for alkaloids in the activated carbon filter were 35 mL triethylamine-trichloromethane solution as the extractant, 35 min ultrasonic extraction time, plus 6 mL sodium hydroxide solution. 2) The retention capacity of the activated carbon composite filter for eight alkaloids was lower than that of the regular filter, resulting in slightly higher cigarette smoke strength. 3) The retention capacity of the activated carbon in the filter for alkaloids was lower than that of the regular cellulose acetate tow in the filter. The retention capacity of activated carbon for eight alkaloids was in the following order: dienenicotine > neonicotine > nicotine > cotinine > myosmine > 2, 3'-dipyridine > anatabine > nornicotine. 4) Adding activated carbon to the filter decreased the retention capacity of the tow in the filter for nornicotine, anatabine, and 2, 3'-dipyridine and increased its retention capacity for the other five alkaloids.