Butt-joint double-protection power source plug extension line

The invention discloses a butt-joint double-protection power source plug extension line. The butt-joint double-protection power source plug extension line includes a male head, a female head and a wire, wherein the male head and the female head respectively include a cylindrical portion and a conical tail portion, wherein the cylindrical portion of the female head is provided with a sleeve ring which protrudes horizontally. The butt-joint double-protection power source plug extension line is characterized in that an inner protective sleeve is bonded to the sleeve ring; the inner protective sleeve wraps the male head and is buckled onto the conical tail portion of the male head; the male head is provided with a protective ring which protrudes circumferentially and obliquely; the protective ring is provided with an outer protective sleeve; and the outer protective sleeve wraps the inner protective sleeve and is buckled onto the conical tail portion of the female head. When the butt-joint double-protection power source plug extension line is used, if cement slurry or sludge slurry permeates the butt-joint double-protection power source plug extension line from fitting slits, the cement slurry or sludge slurry will be firstly blocked outside by the outer protective sleeve, and cement slurry or sludge slurry which permeates from the outer protective sleeve will be blocked outside by the inner protective sleeve again, and therefore, a double-protection effect can be realized, and therefore, the butt-joint double-protection power source plug extension line can work for a long time in cement slurry or sludge slurry environments.