In response to power line inspection, a power line safety distance monitoring and early warning system based on multiple low-cost LiDARs is designed and implemented. The single-line LiDAR (RPLIDAR S1) and RoboMaster GM6020 gimbal motor are combined into three-dimensional equipment for environmental perception. Four sets of the same equipment are installed around an electric bucket for environmental perception. After a target paper is arranged, the point cloud data is collected, and the coordinates of the target paper’s global coordinate system are measured simultaneously. Then the spatial position relationship among the four LiDARs is calibrated according to the least squares principle and unified in the same coordinate system. The real-time point cloud data collected by the four sets of equipment is transmitted to the data processing platform through network communication for visual display, safety distance monitoring, and early warning, which can avoid safety hazards and improve the safety level of live line work.