Ice covering on the transmission line has great impact on power system security.Form-finding of transmission line is the basis for mechanical analysis of iced transmission line by ANSYS.Current form-finding methods end with the convergence of sag or the horizontal stress,which is hard to obtain in transmission lines with height difference while the maximum sag isn't in the center position.Therefore,this paper presented a form-finding method of transmission lines consulting the lowest point.The method obtained the lowest point by analytic method first,then modified the elastic modulus for coming near the lowest point,and repeated the iteration until the line reaches the lowest point after changing the elastic modulus back to actual value.Simulation results show the effectiveness of the proposed method for different types of transmission lines.