Objective: Homalota nanjingensis is a new species found under the bark of Pinus massoniana infected by Bursaphelenchus xylophilus. There were high spatial and temporal encountering probabilities between the H. nanjingensis and the main secondary pests (such as species of Cerambycidae and Scolytidae), showing obvious following phenomenon. Thus, H. nanjingensis could be used as carrier insect with pathogenic organisms to control trunk-boring pest. The investigation of the morphological characteristics, adult feeding habits, and circadian activity rhythm of H. nanjingensis at different developmental stages was conducted in this study to provide references for further research and application. Method: The morphological characteristics of H. nanjingensis larva, pupa, adult were observed and described. Adult feeding habits were studied by indoor-rearing and mouthparts-dissection. The circadian activity rhythm was detected by using "pitfall traps". Result: Experimental investigation showed that H. nanjingensis larva are oligopod, chewing mouthparts, well-developed baenopoda, exarate pupa. The body length is about 1.5-2.0 mm, and body is strongly flattened dorsoventrally, and parallel-sided; The head, elytra and abdominal tergite have VI-VIII segments with dark brown color, and the other parts of the body are yellowish brown. The adults preferred to feed artificially killed springtails, young maggots and larvae of long-horned beetle. When very hungry, it also fed on larvae of Scolytidae, Curculionidae, Elateridae, Formicidae, Labiduridae. We have not found that they preyed on living organisms in the course of experiment. Circadian activity rhythm of H. nanjingensis adult showed two peak hours:8:00-11:00 am and 20:00-22:00 pm. Conclusion: Homalota nanjingensis adult is necrophagy, and its circadian rhythm is influenced by temperature.