Single-crystal sapphire fibers have attracted much attention in high temperature and high pressure environments due to their high melting point, good mechanical properties and stable chemical properties. The preparation method, basic characteristics and high-temperature transmission characteristics of the single-crystal sapphire fiber are introduced. Then, the Fabry-Perot interferometer, Bragg grating and Michelson interferometer based on single-crystal sapphire fiber are discussed. The working principle and implementation methods of these sensors are analyzed. At last, in view of the difficulty of compatibility between single-crystal sapphire fiber and traditional single-mode fiber, the preparation of sapphire-derived fiber and its recent development are introduced. The future development direction of sapphire fiber is also discussed.