Present studies were carried out to determined the structure of Arthropod`s community and their size of 3 sites in Ulsan city, Kyungsangnam-Do. The results obtained were ; 1) Numeral size of Arthropods in the industrial district is comparatively smaller than that in the nonindustrial district where are not polluted so much. 2) Despite of the different composition depending on surveyed area, the insects in order Orthoptera, Hymenoptera, Hemiptera, Coleptera, Collembola and Araneina form the majority part in the surveyed area. 3) Atractomorpha bedeli in Orthoptera, Paratrechina flavipes in Hymenoptera, Cryptocephalus approximates in Coleoptera and Tomocerus varius in Collembola are the common species in the surveyed area. 4) The community of Orthopterous, Hemipterous, Collembolous insects are comparatively higher in nonindustrial area than in industrial area. However, the community of Coleopterous insects is comparatively higher in industrial area than in nonindustrial area.