By using the indices of relative dominance, Levins niche width and Pianka niche overlap, a field investigation was conducted to study the population composition and niches of arthropods under the barks of dead pine trees caused by Bursaphelenchus xylophilus in Zijin Mountain, Nanjing,  China. The populations of the arthropods under the barks of the dead pine trees belonged to 27 species, 17 families, 7 orders and 3 classes, among which, the dominant species were of Poduridae, Staphylinidae, Muscidae, and Scolytidae, the abundant species were of Cheyletidae and Cerambycidae, the common species were of Bethylidae, Bothrideridae, Braconidae and Curculionidae, and the rare species were of Formicidae, Nitidulidae, Thripidae, Histeridae, Labiduridae, Elateridae and Cleridae. The Staphylinidae species had the broadest niche width.
The values of temporal, spatial and temporalspatial niche overlapa and of niche similarity proportion between Staphylinidae and Scolytidae, Cerambycidae were higher than those between Staphylinidae and other species. This suggested that there existed the highest spatial and temporal encountering probabilities and the most obvious following performance between the Staphylinidae species and the main boring insects such as the species of Scolytidae and Cerambycidae. This study could have important theoretical and practical significance for developing the new methods for controlling the boring insects by using the entomopathogens carried by carrier insects.