The vascular plants of Thuja orientalis community in Seokmun-bong, Danyang were listed 222 taxa (4.5% of all 4,881 taxa of vascular plants); 67 families, 150 genera, 163 species, 2 subspecies, 43 varieties and 14 forms. Limestone plants, 29 taxa; Asplenium rutamuraria, Celtis koraiensis, Goodyera coreana, etc. So, Based on the legal protection species, endangered wild plants II, were recorded; Thalictrum coreanum (EN) and rare plants, 8 taxa; Thuja orientalis (LC), Exochorda serratifolia var. serratifolia (LC), Diarthron linifolium (EN), Bupleurum falcatum (VU), Lithospermum erythrorhizon (LC), Dracocephalum argunense (EN), Polygonatum robustum (EN), etc. and endemic plants, 3 taxa; Populus tomentiglandulosa (Planted plant), Thalictrum actaefolium var. brevistylum, Asperula lasiantha, etc. Based on the list of specific plants, 29 taxa; Thalictrum coreanum in class V, 7 taxa (Neillia uyekii for. uyekii, Prunus sibirica, Abelia coreana, etc.) in class IV, 8 taxa (Spiraea trichocarpa, Polygala tatarinowi, Asparagus oligoclonos, etc.) in class III, 2 taxa (Potentilla dickinsii var. dickinsii, Weigela florida) in class II, 11 taxa (Morus cathayana, Buxus microphylla var. koreana, Zizyphus jujuba var. jujuba, etc.) in class I. Based on the list of naturalized plants, 10 taxa (Robinia pseudoacacia, Oenothera biennis, Festuca arundinacea, etc.), naturalization rate (NR) was 4.5% of all 222 taxa of vascular plants and urbanization index (UI) was 3.1% of all 321 taxa of naturalized plants.