C aenorhabditis elegans (C. elegans) was used as an animal model to study the influence of isoflavone daidzein and daidzein metabolites, including dihydrodaidzein (DHD), O-desmethylangolensin (O-Dma) and equol, on lifespan in C. elegans at the concentration of 0.1 mmol/L. The results showed that equol significantly increased the lifespan of C. elegans; however, O-Dma significantly shortened the lifespan of C. elegans. No obvious difference in lifespan was observed when the worms were exposed to daidzein and DHD, respectively. Further study on stress resistance demonstrated that both the thermal and oxidative stress tolerance capacity of C. elegans w as significantly enhanced after being exposed to equol.