To identify the flora of the vascular plant on Chujado Island in Chuja-myeon, Jeju-si, Jeju Province, Korea, eleven field surveys were conducted between April to September of 2013 and from May to September of 2018. The results of the surveys identified 558 taxa, with 97 families, 311 genera, 481 species, two subspecies, 65 varieties, and ten forms of vascular plants on Chujado Island. Of the 558 taxa identified, seven were endemic species and eight were rare plants according to the Korea Forest Service. Furthermore, 109 of the taxa identified were from floristic environments, while 62 were considered to be naturalized plants, with three of these considered to be invasive and causes of ecosystem disturbances. The highest degree of similarity among the plants from seven sites adjacent to Chujado Island was found on Saengil Island, at 51.7%.