Abstract: The problem of suitable plant species sortage severely retarded the research in island vegetation restoration. In this study the photosynthetic characteristics were considered as key indicators to represent the adaptability of plants on island environment. We determined photosynthetic characteristics, water use efficiency (WUE) and specific leaf area of 30 adaptable species in Haitan Island and Dayu Island in summer daytime. We hoped to draw a conclusion for the theory of species selection for island restoration. The result showed that among the conventional species on Haitan Island and Dayu Island, WUEs of Acacia confusaand Pittosporum tobirawere significant different (p<0.05). WUEs of native and introduced P. tobirawere different significantly (p<0.05), but Eurya emarginata was the opposite. Photosynthetic parameters and specific leaf area of 30 species plants are different for their water use strategies against different habitat. Cluster analysis was performed with WUE and 3 categories were grouped from 30 species, accordingly. The WUEs of Nerium oleander, Acacia confusa, Ruellia brittoniana and Calystegia soldanella were high showing strong adaptabilities to the island environment. Therefore, it is significant to select the photosynthetic characteristics as key indicators for screening adaptable plants in island vegetation restoration.