The vascular plants in Obongsan-Kuksabong sector were listed 249 taxa; 76 families, 167 genera, 212 species, 1 subspecies, 31 varieties and 5 forms. Divided into 249 taxa; woody plants were 111 taxa (44.6%) and herbaceous plants were 138 taxa (55.4%). Based on the list of naturalized plants, 7 taxa (Phytolacca americana, Trifolium repens, Oenothera odorata, Erechtites hieracifolia, etc.) and naturalization rate was 2.8% of all 249 taxa of vascular plants. Based on the list of rare plants by the Korea Forest Service and Korea National Arboretum, 3 taxa; Chionanthus retusa (Least concerned), Tricyrtis dilatata (Least concerned), Lilium callosum (Vulnerable) and Korean endemic plants, 5 taxa (Philadelphus schrenckii, Indigofera koreana, Weigela subsessilis, etc.). Based on the specific plants by floral region were total 17 taxa (6.8% of all 249 taxa of vascular plants); Weigela florida in class Ⅱ, 16 taxa (Quercus variabilis, Ulmus parvifolia, Spiraea blumei, Orixa japonica, Ilex macropoda, Grewia biloba var. parviflora, Vaccinium oldhami, Weigela florida, Veratrum versicolor, etc.) in class Ⅰ. The communities of vegetation present in Obongsan-Kuksabong sector separated from 2 sites of Pinus densiflora community, Platycarya strobilacea community and 6 sites of Quercus variabilis community.