Herein, an optical fiber temperature sensor based on a random laser was proposed and implemented. The Rayleigh scattering of the single-mode fiber and the reflection of fiber Bragg grating (FBG) were employed to provide the optical feedback of the laser and achieve a random laser output. Results show that the central wavelength and threshold power of the output laser are 1550.52 nm and 30 mW, respectively. When the pump power is considerably higher than the threshold power, the laser output remains stable. When the temperature of FBG range varies from 30 °C to 90 °C, the output wavelengths of the random laser will shift accordingly, and there is a good linear relationship between temperature and wavelength. The temperature sensitivities of the sensor are 10.5 pm/℃ and 10.4 pm/℃ during heating and cooling, respectively. This type of optical fiber sensor based on random lasers is expected to show diverse application prospects in the temperature sensing field.