Abstract: In order to evaluate the smoking quality of flue-cured tobacco by its routine chemical compositions, the contents of six major chemical compositions, including nicotine, reducing sugar, total nitrogen, potassium oxide, starch and chlorine, in 28 kinds of flue-cured tobacco C3F grown in Henan in 2001 were set pair analyzed by similarity, difference and counter tendency sequence.The results showed that the six major chemical compositions in order of merits were:nicotine, chlorine, reducing sugar, potassium oxide, starch and total nitrogen.It was concluded that the contents of nicotine, chlorine and reducing sugar in these leaves were close to those in quality flue-cured tobacco leaves, while the contents of potassium oxide, starch and total nitrogen in C3F leaves were quite different from quality tobacco leaves, and should be regulated through proper cultural practice and processing technology.