Biological Floating Island (BFI) technology is widely used in water ecological restoration as it effectively improves the water environment on the one hand and builds good visual environment and has economic benefit on the other. The origin and development of BFI are introduced, and biological islands are classified. Researches on BFI all over the globe are also reviewed. Key technologies of BFI and their applications in water ecological restoration are presented based on years of experiences of BFI research and promotion in an illustration of the superiority of BFI technology applied in water ecological restoration. Last but not least, the main development direction is explored.