Abstract: In view of problems of short endurance time, long period of data collection, low accuracy of infrared thermal image and slow data transmission and processing of existing technologies of unmanned aerial vehicle(UAV) monitoring of coalfield fire, UAV monitoring technologies based on single/cluster flight, infrared and visible light dual vision monitoring technology, data transmission and processing technology based on 4G network were studied. Multi-station multi-machine cluster flight mode of UAV is designed, and rapid monitoring of large-area coalfield area is realized through route planning and independent control. Data acquisition is carried out by infrared dual-view thermal imager, the UAV triggers infrared dual-view thermal imager to capture infrared thermal images and visible light images when hovering at an equally spaced waypoint.4G network is used as signal transmission channel, and data acquisition front end and data processing software are synergistically used to realize synchronization of data collection, transmission and processing. Field application results show that two UAVs collect 254 infrared thermal images and 254 visible light images, the data acquisition and image pre-processing takes 150 minutes, and the image synthesis takes 10 hours, monitoring time is greatly shortened compared with existing technology; Coincidence degree of temperature displayed by infrared thermal image and the field temperature test result is above 90%, indicating that using UAV for coalfield fire monitoring is effective and feasible.