Abstract: In order to determine the reasonable harvesting and curing maturity of the upper leaves of Yunyan 87 in the low mountain and hilly tobacco area of Southern Yunnan, by using the comparative experiment, the effects of different harvesting and curing maturity (one-time harvesting and curing 10 days before the technology maturity, one-time harvesting and curing when the technology was mature, and one-time harvesting and curing 10 days after the technology maturity) on the economic traits, appearance quality, physical properties, chemical composition and sensory quality of the upper 6 leaves of flue-cured tobacco were studied. The results showed that the appearance quality, economic traits, physical properties, chemical composition and sensory quality of the upper 6 leaves of flue-cured tobacco were the best when the technology was mature. Secondly, the upper 6 leaves were harvested and cured 10 days after the technology maturity, and the maturity of the tobacco leaves reached complete maturity to over maturity. The sugar-nicotine ratio of the flue-cured tobacco leaves was more suitable, and the contents of protein and nicotine were lower, and the industrial availability was better than that harvested and cured 10 days before the technology maturity. By comprehensively considering the economic traits and industrial usability of the upper leaves of flue-cured tobacco leaves, the upper 6 leaves of Yunyan 87 in the low mountain and hilly tobacco area of Southern Yunnan should be harvested and cured when the upper top 4-6 leaves reached full maturity and the top 1-3 leaves reached maturity.