Abstract: The effects of Protohermes grandis extract on the life-span and reproductive capacity of Drosophila melangogasters were examined. The imagoes were collected by ether anesthesia within 8 h after eclosion. Similar sizes of female and male individuals were selected and cultivated in mediums with different concentrations of P. grandis extract. The number of dead individuals was counted once a day until all the D. melanogasters died. The results showed that,the number of first filial generation male D. melanogasters under treatment of P. grandis extract was significantly higher than that of control group（P<0.05）, while number of F1 femal D. melanogasters showed significant difference only at the concentration of 2.500% P. grandis’s extracts (P<0.01). Weight of all D. melanogasters at the emergence of eclosion was highly significantly heavier than that of control D. melanogasters (P<0.01). What’s more, life-span of female D. melanogasters was also highly significantly longer than that of the control group (P<0.01). Our study provided theoretical reference for better use of P. grandis.