Fiber Bragg Grating (FBG) is a key device widely used in optical fiber communication and sensing. It has many advantages such as high sensitivity, small size and anti-electromagnetic interference. However, it will gradually decline and even be completely erased in a high-temperature environment for a long time, which greatly limits the application of FBG in some special fields such as industrial production, petroleum and electric power, aerospace, etc. Through high-temperature annealing treatment, it is expected that FBG can regenerate thermal regenerated FBG (RFBG), which can work stably in high-temperature environments after high-temperature erasure. Therefore, it is of great significance to study the influence of high-temperature annealing process on RFBG performance. In this paper, based on a 248 nm excimer laser, an initial FBG with a reflection spectrum center wavelength of 1 548.5 nm, a reflectivity of 97.8%, and a 3 dB bandwidth of 0.36 nm is produced by the phase mask method. It is found that FBG achieves thermal regeneration at 950 ℃, and an RFBG with a reflection spectrum center wavelength of 1 546.7 nm, reflectivity of 50.6%, and 3dB bandwidth of 0.19 nm is obtained; further research found that the annealing program after high-temperature thermal regeneration at 950 ℃ has an effect on RFBG The performance has a great impact. The RFBG is annealed by four methods: rapid cooling, slow cooling, natural cooling, and natural cooling in an argon atmosphere, and compared with the initial grating. It is found that the RFBG treated with rapid cooling has the best mechanical performance. It retains about 50% of the mechanical strength of the initial grating, which is better than the slow cooling and natural cooling treatments, which only retain 22.2% and 29.9% of the mechanical strength of the initial grating, respectively. It is found that annealing in argon is beneficial to the mechanical strength of RFBG. The improvement is also natural cooling, and the RFBG annealed in an argon atmosphere retains 43% of the mechanical strength of the initial grating. Further tests on thermal cycling and thermal stability of the RFBG treated with rapid cooling. The results show that the results of the three heating cycles of RFBG at 150~1 050 ℃ completely overlap, the temperature sensitivity is 16.30 pm·℃^-1, the temperature sensitivity correlation coefficient R² is 0.995 38, and the thermal stability test is carried out at 800 ℃ for 7 h, the total wavelength drift amount is only 0.08 nm, indicating that the RFBG prepared in this article has good temperature measurement performance and stability. The research work in this paper provides a certain theoretical and experimental basis for the practical and engineering application of RFBG high-temperature sensors.