We tried to investigate the biodiversity in Yeonpyeong-do Island and the relationship between surrounding environment and ecosystem of other Islands, in order to, eventually, contribute to biodiversity conservation as well as to management of West-coastal islands in Incheon, Korea. Insect had been collected at Yeonpyeong-do Island from April to October, 2010. A total of 209 species of 65 families under 10 orders were identified through this study. Therefore, the species composition of insect over each result from Yeonpyeong-do Island was a total of 10 orders, 77 families, 286 species including 1 endangered species, Lethocerus deyrollei (Vuillefroy), 3 endermic species, 4 management of exotic species and 43 designated species; 93 species of Lepidoptera (32.51%) which is the highest, 50 species of Coleoptera (17.48%), 37 species of Hymenoptera (12.94%) and 33 species of Homoptera (11.54%).