The invention belongs to the technical field of power transmission line high-altitude operation, and relates to a power transmission line high-altitude foreign matter removing tool, which comprises aninsulation rod and an electro-thermal cutting part arranged at one end of the insulation rod. The electro-thermal cutting part comprises a heating head for cutting foreign matters, a temperature control module for controlling the temperature of the heating head and a power supply. On one hand, the structure of a foreign matter on a power transmission line is damaged through high temperature of the heating head without providing a force exerting point with a larger force arm, thereby reducing operation radius or operation space requirements; on the other hand, due to change of the clearing mode, the pulling action is basically eliminated in the clearing process, and the influence of operation on the strength and the safety distance of the power transmission line can be reduced, thereby preventing obvious mechanical damage or increase of damage hidden dangers of the power transmission line caused by operation; and besides, since the requirement for physical strength is low, cutting failure rate is low, and overall operation time of operators is greatly shortened.