To study the temperature sensitivity coefficient of the basalt fiber (BFRP) encapsulated long-gauge fiber Bragg grating (FBG) strain sensor, this paper first introduces the temperature sensing principle of the long-gauge FBG strain sensor, and then selects ten fiber packages with different central reflection wavelengths long-gauge FBG strain sensors for ambient temperature test. The temperature sensitivity coefficient of the fiber-encapsulated long-gauge FBG strain sensor is obtained by fitting analysis of the center wavelength change value of the sensor and the temperature change value. The results show that the central reflection wavelength of the long-gauge FBG strain sensor has a better linear fitting relationship with temperature, and the temperature sensitivity of the BFRP packaged long-gauge FBG sensor is about 20% to 50%, which is higher than that of the bare fiber grating sensor. The temperature sensitivity coefficient measured can directly compensate for the temperature of the BFRP packaged long-gauge strain sensor.