Fiber Bragg gratings （FBGs） have advantages such as excellent multiplexing capability, high sensitivity, compact structure, and corrosion resistance. Therefore, they have been widely used in various practical engineering applications. In this study, we used a 193-nm excimer laser to fabricate a highly reflective FBG array on a standard communication single-mode fiber （Corning, SMF-28）. We performed a long-term annealing experiment for about two months. High-temperature optical fiber sensing systems are designed to achieve quasi-distributed measurement of environment temperature below 400 ℃, with temperature measurement errors of less than 0.2 ℃.