Abstract : A various sizes of ROV are being utilized in offshore industrial, scientific and military all around the world. Due to the innovative development of science and technology, image acquisition devices such as sonar and camera have been reduced in its size and performance has been improved so that, we could expect more accuracy and higher resolution even in the case of exploration using a small ROV. The purpose of this paper is to prepare a standard procedure for identification of unidentified hazardous materials found during the National Oceanographic Survey. In this paper, we propose IDEF modeling technique to identify unidentified objects using small ROV and in accordance with the proposed procedure, an ROV survey was carried out on the target No.16 with the 4tons classed fishing boat as a support vessel on 18th of September 2018 in the sea near Daebu Island. Unidentified objects, which were not known by the multi-beam data obtained from the ship, could be identified as concrete pipes by analyzing the HD camera and high resolution sonar images acquired by ROV. The whole procedure of the proposed can be verified, and the survey with small ROV required about 10 days to identify the target in one place.