Aiming at the problems of large calculation amount and low efficiency in the detection of hidden obstacles in the current UAV patrol inspection of transmission lines, a method for power line reconstruction and rapid detection and analysis of hidden obstacles based on laser point cloud data is designed. Firstly, the method extracts the power line point cloud according to the characteristics of elevation distribution, point cloud density and tilt angle, separates each power line and vectorizes it. Secondly, the method extracts the vegetation point cloud to generate a three-dimensional convex hull. Finally, by calculating the distance between the convex hull point of the vegetation and the power line vector, the efficiency of the tree barrier detection is improved, and the hidden danger information of the tree barrier in the line is quickly detected. Results show that the power line extraction results are complete and accurate, and the power line 3D reconstruction accuracy and the detection efficiency of hidden obstacles are high. This method is robust to transmission line topography, line direction, point cloud density and other factors, which greatly improves the quality and efficiency of transmission line tree barrier hidden trouble detection and provides applications for transmission line tree barrier hidden trouble detection in large-scale complex environments for reference.