Fiber evanescent wave sensor （FEWS） exhibits the advantages of a simple design， high sensitivity， and easy combination with other sensing technologies and is widely used in the field of biological and chemical sensing. Herein， we first describe the definition of FEWS and two types of common fibers and then summarize the optimization methods and principles of FEWS. Second， we review the research advancements of silica and chalcogenide fibers in the fields of gas， liquid， and biological sensing. Finally， the future development trends are prospected.