The result of the study on the flora of the Ulleung-do forest trail's Namyang - Taeharyeong segment showed a total of 199 taxa, including 68 families, 150 genera, 169 species, 26 varieties, 2 Formas and 2 subspecies. 1 species of Trillium tschonoskii Maxim. was observed as a Ministry of Environment-designated endangered species, and the species was observed continuously along the dense hiking trails and valley areas between Namyang and Taeharyeong. It is predicted that damage caused by collecting or stomping by individuals near the hiking region will occur. In terms of the IUCN standard, among species found in the Ulleung-do forest trail region, CR species included 1 species of Calanthe discolor for. sieboldii [Decne.] Ohwi, EN species included 5 species of Cirsium nipponicum [Maxim.] Makino, Lathracea japonica Miquel, Neocheiropteris ensata (Thunb.) Ching, Arisaema takesimense Nakai and Gymnadenia camtschatica (Cham.) Miyabe et Kudo, VU species included 7 species of Adiantum pedatum, Polypodium vulgare L., Taxus cuspidata var. latifolia Nakai, Trillium tschonoskii Maxim., Lilium hamsonii Leichtl., Hepatica maxima Nakai and Phytolacca insularis Nakai, LC species included 7 species of Asplenium scolopendrium L., Tsuga sieboldii Carriere, Maianthemum dilatatum (Wood) A. Nelson & J. F. Macbr., Fagus engleriana Seemen ex Diels, Celtis choseniana Nakai, Tiarella polyphylla D. Don and Campanula takesimana Nakai, and DD species included 2 species of Rumex longifolius DC and Lamium takesimense Nakai. The study observed a total of 20 Korean endemic species, including Athyrium acutipinulum Kodama, Arisaema takesimense Nakai, Fagus engleriana Seemen ex Diels, Silene takesimensis Uyeki et Sakata, Lamium takesimense Nakai and Veronica insularis Nakai. Fagus engleriana Seemen ex Diels especially was found distributed evenly across the study area, and Campanula takesimana Nakai, Rubus takesimensis Nakai and the Hepatica maxima Nakai were observed in small colonies, although the distribution was uneven. Ecologically significant plant species include 15 taxa of Class I, 4 taxa of Class II, 15 taxa of Class III, 27 taxa of Class IV and 2 taxa of Class V, for a total of 63 taxa. Gymnadenia camtschatica (Cham.) Miyabe et Kudo, Hepatica maxima Nakai and Silene takesimensis Uyeki et Sakata are especially exposed to becoming damaged by hikers as a result of their beautiful flowers. Naturalized plant species included the Rumex crispus L., Trifolium repens L., Oenothera biennis L., Veronica arvensis L., Erigeron annuus (L.) Pers., Ambrosia artemisifolia L. and the Sonchus oleraceus L., for a total of 4 families, 7 genera, 7 species and 7 taxa, and it has been assessed that the region included 11% of the entire naturalized plants of the Ulleung-do region. Furthermore, a method of managing and protecting Ambrosia artemisifolia L., which is a Ministry of Environment-designated invasive alien species, must be prepared.