Abstract: In order to find out the main plant resources in Haitan Island, a plant survey was carried out in 6 mountains of Haitan Island from May to September 2018. The results showed that (1) there were 267 species of vascular plants belonging to 221 genera in 87 families, including 35 tree speices, 41 shrub speices, 22 vines species, 169 herb speices, and 32 invasive alien species; (2) dominant families (more than 10 species) were Compositae, Gramineae and Leguminosae, with regional monotypic families and monotypic genera dominanted; (3) Herbs species dominated the growth Type. Leaf features were dominated by single leaf lobular type, leaf coat and non-whole leaf. The flower had a long life. In the fruit type, capsule, achene, stone fruit, and berries were dominant. The environment in Haitan Island was harsh, and the species of plants that could survive on the island were limited to some extent. Plant life types and leaf characteristics all indicated the adaptation of plants to the harsh island environment. The invasion of plants needs more attention.