The invention discloses a clamp for repairing a strand-broken power transmission wire. The clamp comprises a circular arc-shaped loop shell, clamping plates, a left part bolt and a right part bolt; the clamping plate is arranged on the upper edge and the lower edge of the loop shell separately; the left part bolt passes through the left parts of the upper and lower clamping plates and are fastened by a nut; the right part bolt passes through the right parts of the upper and lower clamping plates and are fastened by the nut; and a horizontally movable wire mechanism is arranged between the left part bolt and the right part bolt. The clamp is arranged on the strand-broken power transmission wire in a sleeving manner; an angle of a preformed armor rod winding the power transmission wire is adjusted through the horizontally movable wire mechanism to enable the angle to accord with the winding angle of the original wire; the circular arc-shaped loop shell is elastic and can adapt to power transmission wires of different diameters; and whether the preformed armor rod joint is firmly connected or not and whether the preformed armor rod is tight in winding or not can be directly observed by turning the clamp in a repairing process. The clamp is simple in structure, convenient to operate, and capable of ensuring the repairing quality of the power transmission wire, and improving the overhauling efficiency of the power transmission wire.