Abstract: In order to explore the effect of Astragalus polysaccharide on the life span and antioxidation of D. melanogaster,different concentrations of Astragalus polysaccharide(0.1,0.5,1.0,1.5,2.0 μg/mL)were fed to D. melanogaster. Life span was studied through survival experiment,exercise capacity was studied through negative geotaxis capability experiment,and SOD,T-AOC and MDA activities were determined through antioxidant activity experiment. The results showed that,when Astragalus polysaccharide concentration was 1.0 μg/mL,the average life span of female and male D. melanogaster were prolonged by 27.69% and 25.77% compared with the control. Half death time was prolonged by 52.09% and 53.65%,respectively. The maximum life span was extended by 16.71% and 15.78% respectively,which were significantly higher than the control(P<0.05).Female and male D. melanogaster had the strongest ability to negative geotaxis capability,increased by 14.16% and 27.97% respectively,which were significantly higher than the control(P<0.05). In male and female D. melanogaster,T-AOC and SOD activities were the highest,while MDA contents was the lowest. Astragalus polysaccharide could significantly improve life span,exercise capacity and antioxidant capacity of D. melanogaster.