Lightning is the main cause of transmission line failures. In the past, passive lightning protection and real-time monitoring of lightning through the lightning location system are mainly used in transmission lines. However, early warning of lightning risks in line corridors is not possible. This paper proposes an active early warning method for lightning risks of line corridors based on combined radar reflectivity in consideration of meteorological factors and grid factors. Firstly, the combined reflectivity product covering the entire Guangdong region with a spatial resolution of 1 km×1 km is obtained through network puzzles and matchs with ground flash sample data in the “Easy Flash Corridor”; secondly, based on Gaussian mixture model, the sample data Perform fitting and classify the lightning risk level; Thirdly, the Pearson correlation coefficient between the extrapolated fusion product and the actual situation is analyzed and passed the significance test; Finally, the effectiveness of the proposed method are verified by analyzing actual cases.