To realize environmental thermal image monitoring in a large area, this study took a university training field in Chongqing as an example to investigate UAV regional environmental thermal image monitoring technology. First, the UAV was used for environmental thermal image acquisition, and the Agisoft Metashape software was used for UAV thermal infrared mosaic thermal image processing. The processed thermal infrared images were used for environmental thermal image monitoring and target analysis. Experiments showed that the technology can realize fast processing of regional thermal infrared images, and the processing results can provide an effective reference and basic data for environmental thermal image monitoring and target thermal image analysis.