In order to solve the in-orbit temperature monitoring problem of the optical lens structure of the satellite star sensor,an arc-shaped substrate-packaged fiber grating temperature sensor was proposed.The structural characteristics of the star-sensitive lens and the principle of fiber grating temperature sensing were analyzed.The fiber grating written by femtosecond laser,was used as the sensing element,and an arc-shaped package substrate suitable for the structural features of the star-sensitive lens was designed.The FBG temperature sensor package was completed.The sensor had been tested by tensile test,temperature calibration,and temperature repeatability test,and had been applied in practical engineering.The results showed that the linearity of the FBG temperature sensor with arc-shaped package structure was 0.998,the temperature sensitivity was 8.54 pm/℃,and the change of the center wavelength was less 2 pm at the same temperature,and the strain that caused by deformation of the arc-shaped package structure had little influence on fiber gratings.Satellite on-orbit temperature monitoring showed that the temperature difference between the FBG sensor and electronic sensor was±3 ℃.It can realize the temperature measurement function of the star-sensitive lens structure,and had application prospects in orbit temperature measurement of the star sensor structure.