Abstract: In order to investigate the release characteristics of mainstream smoke of slim cigarette, the routine smoke indexes and neutral aroma components in total particulate matter (TPM) of slim and normal cigarettes from the same tobacco blend were analyzed; the results were compared based on either per cigarette and per unit tar. The results showed that:1) For a single cigarette, the release of TPM, nicotine, tar, CO, moisture content, per puff nicotine, per puff tar and all neutral aroma components in mainstream smoke of slim cigarette was less than that of normal cigarette. 2) For per unit tar, the release of most neutral aroma components was basically the same between slim and normal cigarettes. The deliveries of 2(5H)-furanone, 3-methyl-2 (5H)-furanone, acetophenone, guaiacol, 5-acetoxymethyl-2-furaldehyde, 2-methoxy-4-vinylphenol and methyl linoleate per unit tar were significantly higher, while those of ethyl vinyl ketone, methyl pyruvate, 2-methyl-2-cyclopenten-1-one, limonene and 2, 3-dimethyl-2-cyclopenten-1-one were significantly lower in mainstream smoke of slim cigarette than those of normal cigarette. 3) Different physical indexes (circumference, cut tobacco weight, filter ventilation, draw resistance, etc.) may work with corresponding changes in cigarette combustion and pyrolysis reactions, resulting in these differences of routine smoke indexes and neutral aroma components between slim and normal cigarettes.