Abstract: This paper studied the seismic behavior of the transmission tower under the action of earthquake, Which is based on a project of an actual 220kV transmission line. The transmission tower model and the whole model of the pile-soil- transmission tower system are established respectively by using the finite element software ABAQSU. First, the time history analysis method is used to calculate the dynamic response of the pile-soil-transmission tower system under earthquake load, and the soil is divided into four kinds according to the actual situation. Secondly, the dynamic response of rigid foundation under seismic load is calculated. Finally, the following conclusions are obtained from the analysis of the two different models: After considering the interaction of the system, the period of the structure have extended and the mode of the structure lagged. On soft sites and medium soft sites, compare with no considering the interaction, the results have a big difference, the relative increment of the maximum displacement at the top of the tower is 39.82% and 21.88%，respectively. Therefore it is suggested that the pile-soil-structure dynamic interaction should be fully considered in aseismic design of transmission tower on soft sites and medium soft sites.