Abstract: In order to reduce the excessive nicotine content of upper leaf,field experiments on effects of different plant populations (1480, 1200 and 1025 plants per 666.7m²) on the growth, development, yield, quality and nicotine content of major flue-cured tobacco cv.K 326, Yunyan 85 and CB-1 grown in southeast tobacco growing areas were conducted. The results showed that by properly increasing the plant population, 1)the weight per leaf was decreased,especially for the upper leaf; 2)the proportion of the upper leaf was also reduced; 3)the tobacco leaf (particularly the upper leaf) had lower nicotine content, less irritancy and higher usability.