This paper establishes an intrinsic function model for the displacement of the mounting point under the wind load of the conductor. This paper mainly takes the K1 cross-tower transmission line of 500kV transmission and substation project as the research object. Finite element analysis is used to establish the model and modal analysis is performed on the large-span tower-line coupling model to obtain the vibration modal data. Then, the average wind load is converted to the equivalent static load acting on the tower-line coupled system, and the transmission tower and conductor are mechanically analyzed. The loads at the tower suspension points are determined and a constitutive model of the displacements at these points is constructed. Error analyses of the model and simulated data provide a new perspective on the subsequent study of conductor dancing in transmission lines.