Abstract:This study aimed to investigate the molecular mechanism of rosemary extract（RE）on the life extension of female Drosophila melanogaster.The 2-day-old female D.melanogaster were randomly divided into four groups：control group，low-dose group（0.2 mg/mL RE），medium-dose group（0.5 mg/mL RE）and highdose group（1.5 mg/mL RE）and the medium was changed every three days. Tests regarding lifespan，body weight，food intake and antioxidant enzyme activity as well as intestine anatomy and staining and quantitative real-time polymerase chain reaction（RT-qPCR）were performed on different days. The results showed that adding RE could prolong the lifespan by 13.10% and protect against oxidative stress injury. RE treatment enhanced the activity of endogenous antioxidant enzymes and decreased the content of malondialdehyde（MDA）. In addition，RE inhibited the mRNA expression of mTOR and activated autophagy to maintain intestinal homeostasis.Moreover，RE improved the intestinal barrier function，reduced the abnormal proliferation rate of intestinal stem cells（ISCs）by 35.89%，and improved the intestinal integrity of elderly D.melanogaster.In conclusion，RE could maintain intestinal homeostasis through the key gene PI3K of insulin pathway and the key gene mTOR of rapamycin pathway，increase antioxidant and stress resistance abilities，and thus prolong life expectancy.