Abstract: In order to explore the effects of different harvest time on yield and quality of flue-cured tobacco， with Yunyan 87 as the test material，through field test，three harvest times were set. The results showed that the lower leaves were delayed for 2 days and the middle leaves were delayed for 3 days，the upper leaves delayed 4 days，which had the greatest effect on yield and quality of flue-cured tobacco，which could effectively reduce the total sugar， sugar to nicotine and nitrogen to nicotine. The contents of carotenoid degradation products，the degradation products of cypressin，the products of brownation reaction and the content of new plant diene increased by 18.02%，17.73% and 7.82%，9.85%，respectively. The maturity of flue-cured tobacco was good，the oil was enough，the structure was loose，the tobacco leaves were fully matured and no smoky smoke appeared，and the yield and average price increased. Therefore，through the appropriate delay in harvest can improve tobacco maturation，coordination of fluecured tobacco internal chemical composition content for the production of high-quality tobacco.