Abstract: Eleven upper leaf length segments of Zhongyan 100, a leading variety in middle Henan Province, were selected to investigate the relationship between the main chemical constituents and sensory quality of tobacco leaves with leaf length, and to find the suitable leaf length segments of the upper-six leaves. The results showed that with the increase of leaf length, the ratio of sugar to alkali in the upper six leaves increased first and then decreased; the ratio of nitrogen to alkali decreased first and then increased; the ratio of potassium to chlorine decreased gradually. The aroma characteristics of the upper and lower three leaves and the sensory index of the smoke characteristics were consistent with the change of leaf length, which showed increased first and then decreased with the increase of leaf length. The sensory evaluation had the highest score when the leaf length was 62.90 cm and 69.71 cm respectively. At this time, the sensory quality of the tobacco leaves was the best, and the corresponding chemical composition was coordinated. It is concluded that the length of the upper six leaves has a greater influence on the chemical composition and sensory quality. The leaf length range of the top three and the lower three leaves was 59.80-66.00 cm and 66.22-73.20 cm respectively. At this time, the sensory aroma of the upper six leaves was rich, with good quality and chemical composition.