Alelodes dendrolimi is widely distributed in China. According to the study carried out in Jiangsu and Anhui province during 1982~1984. The average percentage of parasitisms of larvae of Dendrolimus punctatus was 1.8~20.1%. It has 2 generations each year. Winter is passed as larvae within the larvae of 3~4 instar of D. punctatus in over wintering generation. The body of host larvae shortens, and the both ends are slightly narrow, and the middle humps up and looks like a spindle in next spring. It is posited under the bark or on the sprigs and needles pupation period varies from 19 to 24 d. The adults copulates and oviposits on the day time. The longevity of adults varies from 7.7 to 24.7d. The sex ratio reached 1:l.l in 1983, and it was 1:2.5 in 1984. The average percentage of hyperparasitisms was 11.1%. The highest percentage of hyperparasitism was 32% (in first generation). Brachypimpla(?) latopetiolator was observed to be more important than others.