The erasing time and the regeneration complete time of fiber grating exponentially decay with temperature in the temperature interval of 800-950 ℃ when the erasing temperature and the regeneration temperature are the same. According to the fitting function of regeneration complete time, the regeneration threshold temperature of ultraviolet hydrogen loading standard communication fiber grating is 805 ℃. The reflectivity of regenerated fiber grating obeys Gaussian distribution when the treatment temperature is set between 855-905 ℃, which describes the whole regeneration process of fiber grating quantitatively. When the erasing temperature and the regeneration temperature are different, a new method to create a regenerated fiber grating with high reflectivity is obtained, and the method can improve the reflectivity of regenerated fiber grating used in ultraviolet hydrogen loading standard communication fiber from 20% to 43%.