Abstract: In response to the problem of external damage and tripping caused by large machinery entering the transmission line for construction operations, this article draws on the design concept of forest fire prevention checkpoint monitoring and alarm devices, and designs a radar based transmission line movement detection and monitoring device. It is installed at the entrance of locations prone to sudden construction. When the radar detects construction machinery entering the construction site, it triggers the monitoring device to take photos. After the image is recognized as large construction machinery, an alarm is triggered.