Abstract: To seek the best proportion of basal and topdressing fertilizers and time of topdressing, increase the fertilizer utilization efficiency and improve quality of flue- cured tobacco, a field experiment (including 6 treatments and 1 contrast) was conducted in Xuanwei, Yunnan Province, to investigate the effect of different topdressing amounts and time on the quality and economic benefits of‘Yunyan 105’. The results showed that, compared with control, the treatment with 97.5 kg pure nitrogen per hectare, basal and topdressing fertilizer proportion as 70% :30% , and the topdressing of potassium nitrate 25 days after flue- cured tobacco transplanting could promote the regular growth, improve the agronomic characters, coordinate the chemical compositions of tobacco leaves and enhance the smoking quality. Among them, the composite index of chemical compositions was improved by 14.03%, the composite index of smoking quality was improved by 2.93%. In addition, the ratio of mid-high grade leaves, the per hectare yield, the output value and the average price of tobacco leaves increased by 5.05%, 4.79%, 9.98% and 5.45%, respectively, compared with those of control, and the economic benefits were obvious.