Abstract: Studies on species compositions, diversity and flora characteristics in lakesides can provide a scientific basis for lakeside plant community assembly, ecological restoration and reco-very. In this study, species composition, diversity and flora traits in Dianchi lakeside were studied through field investigation, plant identification, sample collection and literature review. Results indicated that 553 plant species belonging to 124 families and 371 genera were found in the investigated area. Of these plants, 370 species were indigenous and 183 species were alien. Furthermore, 11 dominant families such as Gramineae, Compositae, Rosaceae, Labiatae, and Papilionoideae, which included more than 10 plant species in Dianchi lakeside, were observed. The species composition of the flora was concentrated in the families with 1-10 species and in genera with 1-5 species. These findings indicated the abundant species diversity in Dianchi lakeside. Flora analysis showed that floristic types in the surveyed region exhibited complexity and an evolutionary trend of tropicaltotemperate type. The floristic types of spermatophyta mainly belonged to the families of tropical distribution types (47 families) and to the genera of tropical (151 genera) and temperate (165 genera) distribution types. A total of 27 invasive plants were characterized and they belonged to 6 families and 12 genera mostly from the tropics and subtropics. Based on above analysis, ecological restoration and reconstruction strategies for Dianchi lakeside were also proposed.