Transmission line is an important infrastructure to ensure China's energy security. In recent years, rainstorm and waterlogging disasters have occurred from time to time, resulting in the increasing geological disasters of transmission lines, which seriously threatens the operation safety of high-voltage transmission lines. Traditional monitoring methods (GPS and leveling) have limitations in monitoring the deformation of transmission pole tower. In this paper, using the small baseline set (SBAS) technology and sentinel-1a satellite radar data, the cumulative tower foundation variables of a 500kV Line from November 2020 to June 2021 are retrieved. The comprehensive analysis and monitoring results show that the overall foundation of the line is stable, and the tower speed change rate of pole 7 is the largest, which is 25 mm / A. Among them, the deformation in May 2021 has an obvious acceleration process. Combined with the local meteorological conditions and the monitoring and analysis of manual activities, it is inferred that the deformation of the land subsidence area is related to the ground or underground construction process. The results verify the feasibility and effectiveness of this method in surface deformation monitoring and transmission tower structure monitoring along the transmission line.
 

sequential InSAR Technology，,structural deformation monitoring of transmission tower,High voltage transmission technology