In recent years， functional devices based on optical fibers have been widely used. Compared with traditional sensors， optical fiber sensors have many advantages， such as low cost， small size， light weight， high sensitivity， adaptive to severe environment， electromagnetic interference immunity， and so on. This paper reviews the development history and basic concepts of optical fiber. According to the two categories of traditional optical fiber and micro-structured optical fiber (photonic crystal fiber)， the sensing systems applied to temperature， humidity， stress， magnetic field and other parameters are introduced， especially the fabrication of liquid-crystal-injected photonic crystal fiber and sensing application of this type of fiber based on their birefringence characteristics. Finally， this paper proposes the concept of “Lab on fiber” and looks into the future development trends of optical fiber sensing.