Abstract: In order to study the feasibility of replacing the disc insulators with the composite insulators for the 500kV tangent tower, the wind deflection angles of the composite insulator and the porcelain insulator are compared. The transmission line coupling finite element model is established, and the influences of the tower numbers, the wind speeds, the span and elevation differences of the two kinds of insulator strings on the wind deflection angle are analyzed. The results show that the wind deflection angle of the insulator enlarges in varying degrees after the porcelain insulator is replaced by the composite insulator. The changes in the number of gears and the wind speeds has little effect on the increase of wind deflection angle; The span and elevation differences have a great influence on the increase of wind deflection angle; There is a coupling effect among the span, the wind speed and the elevation differences, that is, the smaller the span is, the more obvious the changes of elevation differences on the insulator wind deflection angle, and the more distinct the influence of wind speed on the increase of wind deflection angle. Finally, taking an actual line of a power grid as an example, this paper gives the wind deflection checking results and transformation suggestions. The research results will provide a reference for the transformation of insulators.