A novel temperature sensing structure and packaging process for metal-encapsulated fiber Bragg grating (FBG) temperature sensors were proposed to overcome issues such as aging, creep, and other long-term effects typically seen in traditional adhesive-encapsulated FBG temperature sensors. Finite element analysis was used to design a strain-insensitive sensor. In this new design, glass solder replaced traditional epoxy resin adhesive to secure the FBG to a stainless steel substrate through two-point welding, while a metal shell and silicone rubber provided sealing protection. The FBG temperature sensor demonstrated a temperature sensitivity of 27.46 pm/℃ within the range of -20 to 55 ℃, with a linear fitting degree of 0.999. The sensor exhibited excellent temperature stability and repeatability, achieving a measurement standard deviation of less than 0.003 ℃ across a broader temperature range of 0 to 150 ℃. This packaging structure offers a simple, cost-effective, and easily implementable sensor technology, with promising application prospects in the field of structural health monitoring.