In this paper, several commonly used fabrication methods of fiber grating are described in detail, such as the ultraviolet laser exposure method, CO2 laser irradiation method, arc discharge method, femtosecond laser method and so on. The applicability and limitations of these methods are compared and analyzed. The applications of fiber grating in the field of sensing are systematically reviewed, and some typical sensors based on fiber gratings are discussed, such as temperature, stress, bending, pressure, twisting and biochemical sensors. Finally, the developments of fiber optic sensing technology are summarized and discussed.