A three-dimensional laser radar technology based transmission line tower parameter determination method includes: scanning a transmission line corridor along a line tower by an aircraft-carried three-dimensional laser radar measurement system, and acquiring original laser data and GPS (global positioning system)\IMU (inertial measurement unit) data of specified transmission line tower sections implementing differentiation lightning protection; performing combined fine preprocessing for the acquired original laser data and GPS\IMU data to generate original laser point cloud data after geodetic orientation; performing sophisticated category for the original laser point cloud data to generate LAS format laser point cloud data including surface layers, vegetable layers, line layers and tower layers; and by using professional lightening line tower parameter analysis software, inputting the acquired LAS format laser point cloud data, and analyzing and outputting topography parameters, line parameters and tower parameters accurate to step-by-step towers. The method is capable of providing accurate basic data support for transmission line lightning protection differentiation analysis and research and lightning protection measure effectiveness evaluation.