The variation of main chemical indicators of flue–cured tobacco in the upper, middle and lower parts of three main varieties (K326, Yunyan87, Honghuadajinyuan) in five main producing areas (Changning district, Longling district, Longyang district, Shidian county, Tengchong city) of Baoshan, Yunnan province from 2010 to 2017 were analyzed. The results showed that variations were widely existed in the main chemical components of flue–cured tobacco among different years, in that variation coefficient was large and stability was poor in chlorine content, potassium–chlorine ratio and sugar–alkali ratio of Baoshan tobacco leaves while the stability of total sugar, reducing sugar were good. There were conspicuous differences in chemical composition of flue–cured tobacco among different tobacco areas in Baoshan: the sugar–alkali ratio in Longling district is the most suitable (10.67) and the potassium content is 7% to 26% higher than that of the other four tobacco areas; the nitrogen–alkali ratio is overall low, which is the lowest with Shidian county (0.65), and the closest to the scope of high quality flue–cured tobacco with Tengchong city and Changning district; the chlorine content in Longyang district is 36% – 60% higher than that in the remaining four tobacco areas. The different varieties of flue–cured tobacco had significant differences in potassium, reducing sugar, potassium–chlorine ratio and nitrogen–alkali ratio, and the reducing sugar content of Honghuadajinyuan was 4% and 15% higher than that of Yunyan87 and K326, respectively. Nicotine content in B2F is 56% higher compared to X2F, and the potassium content of X2F (2.35%) is significantly higher than that of B2F and C3F.