In this paper, the sensitized fiber Bragg grating temperature sensor was designed and developed by coating the naked fiber Bragg grating with polyimide, and its temperature sensitivity coefficient was enhanced from 10 to 40pm/℃. Tests were performed on the sensor calibration and temperature accuracy measurement under the test environment of -40~200℃. The test results show that the temperature measurement accuracy can be improved from ±0.4℃ to ±0.1℃ by using fiber grating sensitization package and low-precision fiber grating demodulation instrument in high and low temperature environment. The material characteristics of the fiber Bragg grating temperature sensor with sensitized package were analyzed which can be used to improve the accuracy of temperature measurement, greatly reduce the application cost of fiber Bragg sensor, and lay a foundation for the comprehensive use of fiber Bragg grating temperature measurement.