Abstract: In this paper,the author reports the reproductive system and reproductive behavior of Hepialus baimaensis Liang.The results may be summarized as follows:The female reproductive system of the H.baimaensis is distinctly different from that of the other Lepidoptera insects.It has not the colleterial gland.The male inseminnates the female by the form of the spermatophore which contains sperms as the other Lepidoptera does.These are formed by accessory glands secretion,namely the spermatophore gland,accessory glands and the seminal vesicle.The copulation not only provides the sperms but also promotes oviposition.The parthenogenetic female could lay eggs,but none of the parthenogenetic eggs could behatched,and the number of eggs was obviously decreased.The female reproductive capacity is quite strong.The total number of eggs laid by each female H.baimaensis varies between 364-786.The period of reproduction was short,only 3-7 days.The imago needs 6.2 days for life cycle.The duration of eggs is about 48.5 days (12.6℃).The most suitable temperature and relative humidity for mating and oviposition are 12.5-19.0℃ and 75%-90% respectively.