Abstract: In order to investigate the characteristic of the solanesol content and the relationship between the content of solanesol and main chemical components of tobacco leaf and mainstream smoking of flue-cured tobacco, 266 samples of flue-cured tobacco from 2010 to 2011 year in representative area in China were collected to determine the content of total and free solanesol, the ratio of free solanesol to total solanesol, and those difference among flue-cured tobacco from different ecological regions and different leaf positions and different varieties, and relationship between the content of solanesol and main chemical components of raw tobacco and its mainstream smoking. The results showed that contents of total and free solanesol ranged from 0.21% to 3.48%, and from 0.10% to 2.19%. The average content of total solanesol from north region was lower than any other tobacco regions, but its ratio of free solanesol to total solanesol was the highest. The content of solanesol in tobacco leaves from upper position was higher. The content of solanesol in tobacco variety Hongda was higher than those from Yun97, Yun87, and K326. The content of solanesol in tobacco was significantly corrected to that of petroleum ether extract, cyclohexane extract, total alkaloid, and malonic acid, the same to the amount of mainstream smoking of tar, nicotine, carbon monoxide, benzpyrene, phenol, ammonia, hydrogen cyanide, and NNK. With the solanesol content increased, harmful components in mainstream smoke increased extremely.