This paper fabricated a fiber Bragg grating (FBG) temperature sensor with rapid response and excellent anti-vibration performance. The lightweight and miniaturization of the sensor provided favorable conditions for its application in mechatronic components. Specifically, the Invar capillary with an ultra-low thermal expansion coefficient was selected to package the FBG, which avoided the separation possibility between capillary and FBG under sharp temperature differences. It implied a wide temperature measurement range of the sensor. Nanometer copper suspension filled the tiny gap between capillary and FBG. Its good thermal conductivity brought a fast response speed close to the bare FBG. In addition, the jitter of FBG in the capillary was significantly reduced thanks to the nanometer copper suspension occupying its motion space. This sensor realized the reliability, rapidity and stability together. The FBG temperature sensor was applied to the temperature monitoring of small-size motor for hydraulic pump and achieved ideal results.