The invention relates to a flat opening type ground wire fixture and an application method thereof. The fixture comprises a fixed part, a clamping piece, an elastic piece and a rotation shaft, whereina cavity is formed in the fixed part, a clamping groove, an upper ratchet and a lower ratchet are arranged on an inner wall of the cavity, an opening of the clamping groove is connected with the lower ratchet, the clamping piece can slide relative to the fixed part, two ends of the elastic piece are respectively connected with the clamping piece and the fixed part, the rotation shaft is rotatablyconnected with the clamping piece and extends into the cavity, an upper bulge and a lower bulge are arranged at the periphery of the rotation shaft, the rotation shaft is driven to downwards move bypressing the clamping piece so that the upper bulge is matched with the upper ratchet, the lower bulge is matched with the lower ratchet, and the rotation shaft is further rotated until the lower bulge is clamped into or disconnected with the clamping groove. The fixture has the following advantages that a contact structure of the fixture and a live-line part is not changed, and the requirement ofthe contact resistance between the ground wire fixture and a conductive part and a grounding current is met; and moreover, the fixture is convenient to use, the clamping function can be achieved onlyby aligning the fixture to a conductive part needed to be arranged and upwards lifting the fixture, and the fixture can be taken out by upwards lifting again.