Abstract: Tetrastichus nigricoxae Yang parasitics is mainly observed on the Micromelalopha troglodyta pupae in Xuzhou city. In the microhabitats, the female adult averagely spent (93.12±66.53) seconds to search pupae.The majority of female parasitoids climbs up and insert their ovipositor to the pupae on the host abdomen, Others on the breast and head. One to three days old had no significant influence on the host acceptance behavior of the female Parasitoid, and their parasitization reach 100%. The host acceptance behavior of 4 days old had significant decline, 5 days old’s parasitization rate almost decline to 20%. Tetrastichus nigricoxae Yang can parasitize anaphase larva、early pupae and one to five days old pupa, but it cann’t parasitize 6 days old pupae. Parasitization rate of 1 day old pupae is highest reaching to (92.59±12.83)%. The ability of host acceptance of Tetrastichus nigricoxae Yang gradually descends following the pupae’ age growth. It can not enhance the parasitize after adding the pupae number. Parasitization rate and number of offspring per host enhance gradually when the density of the female chalcid increase. However, hyperparasitization appear when the ratio of pupae to endoparasitoid is 1∶5, it would ascend when the female was endoparasitoid multiplied. Simultaneously, it was found that host pupae movement had no significant effect on its host acceptance.