The invention relates to a wire icing preventer for overhead power transmission lines in the field of power transmission equipment. The wire icing preventer comprises a framework shell, a main shaft, a coupling shaft, a spring, a first gear, a sheave, a second gear, a third gear, a flexible coupling part, an insulator and a wire; the main shaft and the coupling shaft are rotatably mounted in parallel on both side plates of the framework shell; the spring and the first gear are mounted side by side on the main shaft, the outer end of the spring is connected with a fixed shaft on the framework shell, and the inner end of the spring is connected with the main shaft; the sheave, the second gear and the third gear are mounted side by side on the coupling shaft, the second gear and the third gear are engaged with the first gear, and a one-way clutch is arranged at the middle of the second gear; the upper part of the external diameter of the third gear does not have teeth; the flexible coupling part is fixed on the sheave; and the insulator and the wire are connected with the flexible coupling part. The wire icing preventer can remove ice on a power transmission line, so that supporters for the power transmission line can operate under safe load, and thereby, the power transmission line can safely operate under the freezing environment.