[Objectives]  To determine the circadian rhythm of mating, the effect of temperature and duration of mating on aspects of the reproductive biology of the gypsy moth Leucoma salicis (Linnaeus), such as adult longevity, oviposition and hatching. [Methods]  Newly emerged adults were collected，meanwhile the circadian rhythm, and the effect of temperature on mating, oviposition, and hatching were observed. [Results]  The results show that mating started between 03:00 and 05:00 and that the mating peak period was at 04:00. The peak day for female oviposition was the 2^nd day after emergence. However, the duration of mating at 25℃ (9.2 h) was significant shorter than that at 28℃ (11.8 h). The duration of mating affected the longevity of both male and females, the longevity of female adults significantly increased compared to the control (9.2 h) when mating was interrupted after periods of 30, 60 or 300 min, respectively. The longevity of male adults was significant longer than the control after only 60 min mating. The shortest mating time of 30 min had the lowest oviposition and egg hatching rates. [Conclusion]  There was no difference in the fecundity or longevity of adult males or females at relatively favorable temperatures from 25 to 28℃. However, adult longevity oviposition and hatching rates were significantly affected by the duration of mating.