In Mt.Baekun in Yeongjong island, there is Pinus thunbergii community, so there are many insect species. We caughtinsects to investigate entomofauna in dead pine tree. The tree is about 6 months later after dead, so fungis grow there.And it contains much moisture and it is located about 100 altitude. Caught insects were treated by ethanol, and larvaeswere made into immersion specimen, and the others were made into exsiccata. Also, we divided the tree in 5 parts inheight, and 3 parts in radius. The most frequently appeared species were cerambycidaes. Many species appeared suchas Peseudo japonicum, insularis Motschulsky. Moreover, we confirmed many insects inhabit there, such as Pentatomidaes,Elateridaes. And insect distribution changes by height and radius. This shows even just one dead tree forms a small ecosystem,and suggests necessity of environmental preservation.