In order to achieve effective supervision of transmission line corridors, a method of power line extraction and reconstruction was proposed based on airborne laser radar(LiDAR) point cloud. Firstly, echo information of point clouds was used to filter out the most of ground objects and keep all information about power line. And then, most non-power line point clouds were removed based on grid height elevation and elevation threshold. The initial extraction of power line was realized. For the preliminary extracted point cloud of power line, a single transmission line point was separated by Hough transform. In order to improve the accuracy of power line point extraction, the extraction result of Hough transform was improved. Then the location of the tower was determined by means of local extreme point detection. Finally, a polynomial model with constraints was used to segment each power line and realize 3-D reconstruction of power line model. The results show that, 424 power line points are extracted by this algorithm and the total extraction accuracy is 87.603%. The fitted power line model has a good effect. The algorithm can automatically and accurately extract and reconstruct power lines from LiDAR point cloud data. It has a good practical value for the inspection of transmission line corridors.