This study was carried out to investigate the flora of indigenous habitat of Donghae-si and Samcheok-si in Gangwon-do, Korea. The vascular plants were collected 18 times (from March to October 2011), and were identified as 804 taxa; 127 families, 445 genera, 720 species, 8 subspecies, 69 varieties, 5 forms and 2 hybrids. In the flora of this area, the calcicolous plants were 55 taxa; Cheilanthes argentea, Clematis serratifoliam, Quercus variabilis. Epipactis papillosa, etc. The endangered plants designated and protected by the wildlife protection law, the Ministry of Environment, Korean were counted to one taxon; Cymbidium macrorhizum. The red list of vascular plants according to IUCN valuation basis were examined, endangered species (EN); Prunus yedoensis and Cymbidium macrorhizum, Vulnerable species (VU); Juniperus chinensis, Pulsatilla tongkangensis, Diarthron linifolium and Swertia wilfordii, Near Threatened species (NT); Paeonia japonica, Allium senescens, Epipactis papillosa and Pogonia minor, Least Concern species (LC); Asplenium ruta-muraria, Platycladus orientalis, Monotropa hypopithys and Eleutherococcus divaricatus var. chiisanensis, etc., Data Deficient species (DD); Paeonia lactiflora var. trichocarpa, and Not Evaluate species (NE); Prunus choreiana, Panax ginseng and Polygonatum infundiflorum etc. Korean endemic plants of this area were 26 taxa; Aconitum pseudolaeve, Corydalis hirtipes, Vicia chosenensis, Salvia chanroenica and Hemerocallis hakuunensis, etc. The floristic regional indicator plants found in this area were 130 taxa comprising 11 taxa of grade V, 15 taxa of grade IV, 33 taxa of grade III, 15 taxa of grade II, 56 taxa of grade I. The naturalized plants were identified as 67 taxa and the percent of naturalized index (NI) was 8.3% of total 804 taxa vascular plants.