The energy project of “West-to-East Power Transmission” has been vigorously implemented. Transmission towers are inevitably built on steep slopes, and the stability of such slopes is directly related to the safe operation of transmission lines. Taking the landslide of a 500 kV tower in Jiangzi as an example, based on the finite element numerical simulation method, the seepage stability and dynamic response analysis models of the tower landslide were established respectively to study the differences in landslide deformation of the 500 kV tower landslide in Jiangzi under short-term heavy rainfall and continuous moderate rainfall conditions, and the dynamic response of ground motion to the tower landslide was further analyzed. The research results show that rainfall is the main factor inducing the landslide of Jiangzi 500 kV tower. Under the infiltration of rainwater, the landslide will slide along the potential sliding surface, but the displacement at the rear edge of the landslide is small, and the overall slope body remains in a stable state, posing no significant threat to the normal operation of the transmission increase significantly, resulting in a decrease in the shear strength of the soil and an increase in the sliding force, which makes the slope deformation more severe. Under the action of earthquakes, the dynamic response characteristics of the tower and slope are manifested as the acceleration amplification factor gradually increasing with the increase of height. Moreover, with the increase of seismic acceleration, the seismic inertial force breaks through the shear strength threshold of the slope, triggering the instability and sliding of the slope-tower base system. The flexible constraint of the conductor and the sliding process generate a dynamic coupling effect, eventually leading to the instability and failure of the tower legs.