Changes of biochemical indicators and antioxidant activity in vitro of plant ferment during fermentation were studied, and the effects of plant ferment on the lifespan of Drosophila melanogaster and antioxidant activity in vivo were also investigated. The results showed that pH values decreased from 4.11 to 3.50 continually during fermentation. Reducing sugar content decreased firstly, increased subsequently and then decreased at last, reaching 78.78 ±3.24 mg/mL in the end of fermentation. The contents of total acids and total polyphenol content reached 9.80±1.06 mg/mL and 55.04±1.36 μg/mL, respectively. The DPPH free radical scavenging ability and reducing power of the plant ferment increased during the fermentation. Besides, the half death time, average lifespan, and maximum average lifespan of male drosophila were significantly improved with the addition of 2% plant ferment in basic culture medium (p<0.05), which were higher than those of the CK group (22.60%, 15.44% and 10.82%, respectively).. The half death time and maximum average lifespan of 2% dosage group of female were significantly higher than that of the control group, and the average maximum lifespan of 1% dosage group was also significantly higher than that of control group dramatically (p<0.05). In addition, the activity of SOD of Drosophila Melanogaster in 2% dosage group was higher and the content of MDA was lower than that of the control group (p<0.05). An obvious effect of plant ferment on decline degree of MDA content was also found.