Coccophagus ceroplastae is an important parasitic wasp, endoparasitizing the 2nd and 3rd instar larva of Parasaissetia nigra. In this paper, the morphological characteristics of C. ceroplastae were described, and behaviors, development, survival, and reproduction of the wasp were also studied in the lab. The results showed that life cycle of C. ceroplastae lasted 21-26 days, including eggs, 3 larva instars, prepupae, pupae and adults. Duration from eggs to pupae was 14-17d, and that of pupae was 7-9d. The reproductive system of female was located in the abdomen, with a pair of eudipleural ovaries, and each ovary consisted of 3 ovary tubes. The ligament composed of terminal filament was separate, and didn′t joint to median ligament. Ovaries started to develop in the pupa phase. Some eggs are matured in 6-day-old pupae. Mature eggs in the ovaries reached 63.9, 154.7, and 163.2 in 7-day-old pupae, adults just emerged, and adults one day later, respectively. Addition of nutritions in the adult phase had no significant effects on egg number, which indicated that C. ceroplastae is a pro-ovigenic parasitoid. Mating happened just after eclosion and lasted 2-3 seconds, and there was mating competition behavior among male wasps. Male wasps could mate several times, but female ones could only mate once. Mating obviously promoted oviposition. An unmated and mated female wasp laid averagely 2 and 164 eggs, respectively, in the 3rd instar nymph of P. nigra, under the same conditions, which were 82 times in the difference. C. ceroplastae oviposited after mating, and oviposition duration lasted 5-8 seconds. Oviposition behavior included host searching, host inspecting, ovipositor probing, laying eggs and ovipositor pulling out. The wasps had poor ability to distinguish between parasitized and unparasitized hosts. Superparasitism existed, and one wasp might lay eggs repeatedly in a single host, but only one egg could develop into adults. Eclosion peaked in 8:00-10:00am. There was a circular eclosion hole, with irregular edges, about 0.2-0.6 mm in diameter, located in the back of dorsal raphe near the anal cleft of host. Temperature, relative humidity (RH), and photoperiod affected eclosion rhythm of the wasp. Eclosion peaked during 08:00-10: 00 AM at 20 and 24℃. Under suitable temperature, eclosion emerged intensively. Proportion of eclosion reached 89.36% and 88.89% during 08:00-10:00 AM at 20 and 24℃, respectively. The peak of eclosion happened during 06: 00-08: 00 AM at 14℃, with only 31.71% adult eclosing. Eclosion peaked during 06: 00-08: 00 and 08: 00-10: 00 AM at 20% and 30%-90% RH, respectively. At the photoperiod (L∶D = 12∶12), eclosion emerged intensively, with 88.89% adult eclosing during the eclosion peak. Longer or shorter photoperiods could scatter eclosion. Temperature and addition of nutritions had significant influences on longevities of adult wasps. Female wasp lived shorter, with the increasing of temperatures. At the same temperature, addition of nutritions offered could prolong the longevities of adult wasps, and to a greater extent with the increasing of nutrition concentration. The longest-lived adult wasps were those offered 10% sucrose, secondly 10% honey, lastly offered clear water or no nutrition.