Abstract: Real-time and accurate acquisition of wind speed data is helpful for precise control of mine wind flow. The existing mine wind speed sensors such as hot-wire type, impeller type, ultrasonic vortex street type and differential pressure type are either susceptible to interference, or unable to detect breeze, or small ranged. Moreover, all these sensors obtain wind speed through electrical signals, and there are safety risks. Based on the light-to-heat conversion characteristics of doped optical fiber and fiber Bragg grating(FBG) temperature measurement principle, a mine-used hot-wire-based optical fiber wind speed sensor is designed. The light energy is converted into heat energy through the doped fiber, and demodulating the amount of FBG center wavelength drift under heat exchange is used to calculate the temperature change of the sensor probe and the wind speed. In the FBG demodulation process, the grating multiplexing technology is applied to realize multiple sensors sharing the same light source and demodulator, which reduces the cost. Laboratory test results show that the FBG center wavelength drift is non-linearly related to wind speed. In the lower wind speed range, the higher the pump light source power, the greater the FBG center wavelength drift range, and the higher the wind speed detection sensitivity. When the wind speed is 0-0.57 m/s, the sensor sensitivity is 1 370 pm/(m·s-1), and the highest resolution is 0.7 mm/s. The response time of the sensor decreases with the increase of wind speed, and the wavelength dynamic range increases with the increase of wind speed. The field test results show that the sensor can realize the detection of breeze and low wind speed in coal mines with good stability, and the monitoring value can show the change of wind speed on site accurately.