To investigate effect of Epimedium flavonoids (EF), positively controlled by caloric restriction (CR) method, in retarding aging of the model organism C. elegans, in order to establish a basis for studying its action mechanism. Experiment for life-time analysis was conducted on animals grouped into the blank group, the CR group, and the high and low dose EF groups to observe their mean lifespan, maximum lifespan and age-dependent mortality. And the reproductive capacity test and acute heat-stress analysis were carried out in the blank group and the high dose EF group to observe the subalgebra and the mean survival time under acute heat-stress at 35 degrees C. As compared with the blank group, the mean lifespan in the two EF group and the maximum lifespan in the high dose EF group were higher, and the age-dependent mortality in the high dose EF group was lower significantly (P<0.05 or P<0.01); as compared with the CR group, the mean lifespan and maximum lifespan in the high dose EF group were higher (P<0.01); but no significant difference of the subalgebra between the blank group and the high dose EF group was shown (P>0.05). Compared with the blank group, the mean lifespan in the high dose EF group was significantly prolonged under acute heat-stress at 35 degrees C (P<0.01). EF can retard the aging of C. elegans without damage on the reproductive capacity, and significantly improve its capacity against acute heat-stress.