To reduce the impact of icing on a power grid， a method based on the controllable line losses by reactive power control is presented. For the propose of anti-icing， the iced line current is gradually increased through regulating reactive current to increase the line loss. To maintain the safety of the power system， the current through the iced line is slightly greater than the critical current. In this method， the heat produced by the working current through a line is used to balance the heat for icing. As a result， the ice formation condition is broken. The proposed method is verified by MATLAB on the IEEE-30 system. The simulation results prove its feasibility and effectiveness. The comparison of the local reactive power adjustment， the local reactive power optimization and the optimization of the whole network reactive power control shows that the whole network optimization of reactive power compensation control is the best with the minimal system loss.