Distributional surveys for vascular plants were carried out in Daecheong island, Ongjin-gun, South Korea, from 2008 to 2010. The vascular plants recognized from the island were in tatal 402 taxa that were of 90 families, 269 genus, 350 species, 3 subspecies, 43 varieties, 6 forms. Among the investigated 402 taxa, 2 Korean endemic plants, 8 rare and endangered plants which was designated by Korea Forest Service, 35 specially plants designated by the Ministry of Environment were included. The naturalized plants were identified as 40 taxa and the percentage of naturalized plants index was 9.9%. In addition, an unrecorded species, Thyrocarpus glochidiatus Maxim (Boraginaceae), was recognized from the island.