Abstract: In order to investigate the optimal condition for mass rearing and storage of Aphidius gifuensis Ashmead, the variation of diapause rate of a dominant endoparasitoid of Myzus persicae (Sulzer) in tobacco-planting areas were studied under different temperatures and photoperiods. The results showed that under short-day condition (Light:Dark=8:16) at the temperature of 0℃, 5℃ and 10℃, the diapause rate of A. gifuensis was 71.12%, 55.50% and 45.71%, respectively; while under long-day condition (Light:Dark=14:10) at the same temperature, the diapause rate decreased to 44.53%, 24.18% and 0, respectively. However, the diapause of endoparasitoids was not induced at 25℃ and 30℃ either under long-day or short-day condition. It indicated that the interaction between low temperature and short-day increased the diapause rate of A. gifuensis, while long-day and high temperature inhibited its diapause.