Abstract: In order to monitor the potential fire hazard existing in long-term continuous operation of long-distance belt conveyors in coal mines,a distributed optical fiber temperature sensing method based on the temperature-sensitive characteristics of backward Raman scattering light and optical time domain reflection is proposed for fire monitoring and warning along the belt conveyor.The principle of temperature monitoring and positioning along the belt conveyor is theoretically analyzed,and a distributed fire warning scheme is designed.Besides,a data processing method by combining ensemble averaging and wavelet transform is utilized to improve the signal-noise ratio and real-time performance of the system simultaneously.The experimental results show that the optical fiber sensing detection method can achieve temperature monitoring within 10 km range response time is less than 3 s and the positioning accuracy is less than 2 m,and the measurement range can reach 190 ℃.Therefore, reasonable laying of optical fibers and using this sensor system can provide timely and effective fire situation along the belt conveyor in coal mine, and provide guarantee for the safety of coal mine production.