Fifty–four samples of tobacco variety K326 from main tobacco producing areas of Hunan province were collected to explore the relationship between medium–trace element contents and chemical components in tobacco leaf of Hunan province. Medium trace–elements boron (x1), manganese (x2), iron (x3), copper (x4), zinc (x5), molybdenum (x6), magnesium (x7), calcium (x8) and chemical components sugar (y1), reducing sugar (y2), total nitrogen (y3), nicotine (y4), chlorine (y5), ratio of nitrogen to nicotine (y6), ratio of sugar to nicotine (y7), potassium (y8) and ratio of potassium to chlorine (y9) were determined and investigated by correlation analysis and stepwise regression analysis. The results show that the contents of the medium–trace elements had significant correlation with chemical components. Stepwise regression analysis further proved that total sugar (y1) was mainly influenced by copper (x4) and calcium (x8), and was positively correlated with calcium while significantly negatively correlated with manganese; total nitrogen (y3) was mainly affected by manganese (x2), copper (x4) and zinc (x5), and was positively correlated with manganese and copper while showed significant negative correlation with zinc; ratio of nitrogen to nicotine (y6) was mainly influenced by copper (x4) and was significantly positively correlated with copper; ratio of sugar to nicotine (y7) was mainly influenced by manganese (x2) and was significantly negatively relative to manganese. The stepwise regression equations are y1=23.490–0.334x4+2.441x8, y3=1.106+0.003x2+ 0.018x4–0.005x5, y6=0.570+0.021x4 and y7=19.657–0.048x2. In Hunan tobacco area, the chemical availability of tobacco leaf can be improved by adjusting the content of manganese, copper, zinc and calcium in tobacco leaf. In the case of lower levels of sugar: nicotine ratio in Hunan, it can be improved by reducing the copper and manganese in the tobacco leaves, or increasing the levels of zinc and calcium in the tobacco leaves.