For the current inspection mode of high-voltage transmission lines in power grid of China, it is mainly through manual hand-held instruments or naked eyes to inspect facility defects,which is not only difficult and intense, but also inefficient, and cannot adapt to the safe operation and development of modern power grid. In recent years, with the rapid development of unmanned aerial vehicle technology and related sensor technology, unmanned aerial vehicle has been widely used in electric inspection. Therefore, a real-time localization and map construction (SLAM) scheme based on lidar and unmanned aerial vehicle near high voltage tower is proposed. In this scheme, lidar is used as the sensor to sense the environment, different matching algorithms are used to match the secondary point cloud, and loopback detection technology is used to achieve the precise positioning of unmanned aerial vehicle and the map construction around the tower. Experimental results show that this scheme can greatly improve the positioning accuracy of unmanned aerial vehicle around the pylons, thus improving the efficiency and flight safety of unmanned aerial vehicle.