The phenomenon of creep and aging is ubiquitous in the traditional FBG sensors packaged by adhesive.To solve the problem,a kind of metallic-packaging FBG sensor based on one-step ultrasonic welding was proposed.Strain-insensitive structure of temperature sensor was designed by finite element analysis method,and the performance of temperature sensor was tested.The experimental results show that the metallic-packaging FBG sensor is insensitive to axial strain.And the temperature sensitivity reaches 39.16 pm/ ℃,which is as 4 times as that of bare FBG.The fitted linearity exceeds 0.999,and it has excellent repeatability.Furthermore,the dynamic response time is less than 30 s from 20 ℃ to 100 ℃.The metallic-packaging FBG temperature sensor had the advantages of simple process,short production cycle,and excellent temperature sensing characteristics.It has extensive prospect in the field of high-precision and high-reliability sensing.