Abstract: Effect of maternal photoperiod experience on diapause incidence of Cotesia plutellae was examined in laboratory by exposing mother generation (G0) to 3 photoperiod regimes (8L∶16D, 12L∶12D and 16L∶8D) at 25℃, and exposing their offspring (G1) to 2 photoperiod regimes (8L∶16D and 11L∶13D) at 4 temperatures (13, 15, 17 and 20℃). The results indicated that all three diapause-inducing factors, maternal photoperiod experience, offspring rearing temperature and photoperiod, had significant influence on diapause incidence of the parasitoid. Interactions between any two factors were significant. However, the integrated interaction among three factors was not significant. Long day-length experience in G0 lowered the critical temperature for diapause-inducing in G1. The photoperiod experience in G0 had least influence, even no influence on the incidence of diapause when G1 was reared at lower temperatures, but it had an obvious effect on the incidence when G1 was reared at relative higher temperatures.