Abstract: The relationship between the chemical compositions of flue-cured tobacco (B2F and C3F) in Guangdong’s 6 counties and geographical, ecological characteristics was studied. The results showed that the characteristics of Wuhua and Meixian’s tobacco was High-carbohydrate content and Low-nitrogen compounds content, because of good light and heat conditions. Jiaoling’s tobacco had low-carbohydrate content and high-nicotine content being related to its large rainfall and high-temperature. Nanxiong’s tobacco characterized by low –total-sugar content，low-reducing-sugar content, high nicotine content in upper leaves and low nicotine content in middle leaves, had some connection with alkaline soil. The feature of Lianzhou’s tobacco was high total sugar content, high reducing sugar content and high nicotine content in upper leaves, having to do with its soil and too much rain in mature stage.