These studies were conducted to investigate the changes of starch, sugar and nicotine content in relation to maturity and cultural conditions and correlation between growth characteristics and chemical components in order to improve the leaf quality. The results were summarized as follows; 1. Nicotine content, total nitrogen content and the ratio of total nitrogen to nicotine of the green leaf were increased with heavier fertilizer, wider planting space and lower topping, whereas starch, total sugar and the ratio of sugar to nicotine were decreased. 2. Starch content, sugar content and the ratio of total sugar to nicotine(T-S/Nic) in the cured leaf were decreased with milder planting space, less application of MH and delaying harvesting date. 3. It was estimated that 58.1% of starch of the harvested leaf was converted into sugar of the cured leaf, and also they were significantly correlated each other.