Abstract: In order to understand the plant species composition and the relationship between plant functional traits and environmental adaptability on uninhabited islands, the field investigation and data consulting were conducted on six uninhabited islands in Pingtan District. The results showed that: (1) The small area of uninhabited islands led to fewer species. A total of 70 species of vascular plants belonging to 41 families and 70 genera were found on six uninhabited islands in Pingtan. The investigated seed plants were all angiosperms, among which Compositae (9 species, 9 genera) and Gramineae (7 species, 7 genera) were dominant families. (2) There were 19 alien invasive species, accounting for 27.14% of the total species, with Compositae and Gramineae as the main species. (3) Herbs were the dominant plant growth types in the six uninhabited islands of Pingtan. In terms of life form, high buds plants were the most, and cryptobud plants were the least. In terms of leaf functional traits, leathery leaves, small leaves, single leaves, whole leaves and hairy leaves were the most. The main types of fruits were dry fruits such as capsule, achene and drupe. The main ways of seed dispersal were wind dispersal, self-dispersal and other abiotic dispersal. Through this study, the composition and functional traits of plants in the six uninhabited islands of Pingtan were understood, which could provide reference for the protection, development and rational utilization of the ecosystem in the study area.