The invention discloses a line foreign material removing device based on an unmanned aerial vehicle, which comprises an unmanned aerial vehicle delivery mechanism and a foreign material removing mechanism. The unmanned aerial vehicle delivery mechanism comprises the unmanned aerial vehicle and a clamp and a control unit for controlling the clamp to be opened and closed, which are arranged on the unmanned aerial vehicle; and both ends of the foreign material removing mechanism are respectively connected with insulating ropes. The line foreign material removing device disclosed by the invention is simple to operate, safe, reliable, high in efficiency and low in cost, can effectively remove foreign materials on a power transmission line in a live case, has a wide market space and is suitable for energetic popularization and application.