Abstract: Glyptapanteles liparidis (Bouche) has 4 generations a year in northern China and parasitizes Lymantria dispar in its first two generations. The hosts of the later two generations are Pine Caterpillars. It overwinters in the overwintering larvae of Dendrolimus spp.. The lifespan of egg-larval stage is about 25~35d, pupal stage 6~8 d, adult stage of ♀8~14 d, ♂5~10 d. The adults come out from cocoons consistently and have a high rate of emergence. The 2nd-instar larvae of the hosts is the best fitness stage for parasitization. It has a high reproduction rate of 636±176 per female and the maximum 953. Cold-stored pupal stage cocoons have no effects on the emergence, but when cold-storage takes place in the prepupal stage, the rate of emergence can be reduced obiviously. All the adults which emerge-nced from the cold-stored cocoons have a tendency of shortened lifespan. Both the rearing density and the diet for adults are important factors for its longevity.