Abstract: To investigate the feasibility of establishing a commercial grading system for flue-cured tobacco and maximize the value in industrial use of tobacco, the relationships between appearance quality and major chemical components of flue-cured tobacco grown at Yuxi in Yunnan Province were studied.The results showed that:1) the contents of nicotine, volatile bases, chlorides and total nitrogen decreased, the content of reducing sugar increased first and then decreased, and potassium content increased with the descent of stalk position;2) in lighter leaves, the content of reducing sugar was higher than that in darker leaves at the same stalk position, while the contents of nicotine, total nitrogen and chloride were lower;3) the content of reducing sugar increased and the contents of volatile bases, chlorides, total nitrogen and nicotine decreased with the decrease of maturity of tobacco leaves;and 4) in tobacco leaves with heavier body, the content of reducing sugar was lower, while the contents of nicotine, volatile bases, chlorides and total nitrogen were higher.