The invention provides a method for processing a tungsten helical line of a millimeter wave traveling-wave tube, which comprises the following steps of winding the tungsten helical line on a core rod, copperizing the core rod and the tungsten helical line, melting the copper at high temperature, fixing the tungsten helical line and the core rod together (wherein the melting temperature can not lead the tungsten filament to become brittle), carrying out processing of grinding so as to ensure the external diameter of the tungsten helical line, continuing to eliminating the stress of the tungsten helical line and the core rod at the high temperature after finishing the processing (the high temperature can not lead the tungsten filament to become brittle.), and sequentially removing copper and corroding the core rod by a solution so that the tungsten helical line is separated from the core rod, thus completing the fabrication of the tungsten helical line. The method has the advantages of meeting the precision requirement of the millimeter wave traveling-wave tube; ensuring no changes of the pitch of the tungsten helical line during the process of winding, high-temperature processing and processing of grinding; and utilizing the high-temperature processing method twice so as to ensure the tungsten filament difficult to become brittle and meet the use requirement of the traveling-wave tube.