Abstract: The relationship between alkaloid content of flue-cured tobacco and ecological factors in the central region of Guizhou Province was analyzed. 25 samples of soil and the corresponding tobacco leaves (C3F) were collected from the central region of Guizhou Province. The contents of five main alkaloids including nicotine, nornicotine, myosmine, anabasine, and anatabine in tobacco leaves were determined by gas chromatography. The correlation between ecological factors and alkaloid contents and components were analyzed. The content of nicotine was about 2.83% in the central region of Guizhou Province. The order of content of the 5 main alkaloid in tobacco leaves was:nicotine> anatabine> nornicotine> anabasine> myosmine. Significant correlation between precipitation, humidity of the air, air temperature and diurnal temperature and alkaloid contents were found. No significant correlation between ground temperature, sunshine time and alkaloid contents was found. The precipitation and diurnal temperature strongly affected the contents of anabasine and anatabine. The content of alkaloid components increased with the increasing content of soil alkaline hydrolysis nitrogen. The positive effects between content of nicotine and anabasine and soil pH were found, while the content of myosmine and effective potassium of soil had negative effect. Significant correlation between precipitation, humidity of the air, air temperature, diurnal temperature and soil alkaline hydrolysis nitrogen and alkaloid contents were found.