The invention discloses a portable electric power construction earthing device and an application method thereof, and relates to the technical field of electric power. The portable electric power construction earthing device comprises an insulation operating lever and an earthing head, and is characterized in that the earthing head is connected with the insulation operating lever through a universal joint; the insulation operating lever comprises an upper telescopic rod and a lower telescopic rod; the upper telescopic rod sleeves the lower telescopic rod; the upper end of the upper telescopic rod is fixedly connected to the universal joint; the lower end of the upper telescopic rod is provided with a boss; the boss is connected to a supporting frame through a rotating shaft; the lower part of the lower telescopic rod is uniformly provided with grooves; the bottom end of the lower telescopic rod is fixedly connected to the upper end of a pedestal; the pedestal is internally provided with a wire barrel; two ends of the wire barrel are connected to supporting base through a rotating shaft; the supporting base is welded at the bottom part of the pedestal; and one side of the wire barrel is fixedly connected to a rotating handle.