The in vitro antioxidant activity of fermented qushi decoction (FQD) was evaluated based on the free radical scavenging capacity. The results showed that the total antioxidant capacity of the high-dose FQD group was significantly higher than that of the unfermented qushi decoction (QD) group. In particular, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging rates and the total antioxidant capacity significantly increased by 24.38%, 11.98%, and 11.76%, respectively, in the high-dose FQD group. FQD showed no significant effects on the total egg production of Caenorhabditis elegans. However, the average lifespan of C. elegans increased by 8.02% to 26.36% after FQD intervention. Under heat stress and oxidative stress conditions, the maximum survival time of C. elegans was extended by 25% and 16.67% in the FQD groups, respectively. In addition, the antioxidant enzyme activity of C. elegans was significantly enhanced (P<0.05) and the level of lipofuscin accumulation was reduced after FQD intervention. In conclusion, FQD provides anti-aging effects on C. elegans by increasing the in vitro antioxidant capacity, prolonging the lifespan of C. elegans, enhancing stress resistance, and improving the antioxidant enzyme activity. This study tentatively indicates that FQD has anti-aging effects, and the findings provide a theoretical basis for the development and utilization of related nutraceuticals.