The invention discloses a cable skinning knife, comprising a knife handle and a knife blade. A knife head is arranged at one end of the knife handle. The knife head and the knife handle are two independent structures which are fixedly connected, or an integrally formed whole structure. A groove for mounting the knife blade, a cut support part, a locking block and a locking bolt are arranged on the knife head. The cut support part is located on the knife head at the other end opposite to the end connected with the knife handle. The groove penetrates the cut support part. The knife blade is arranged in the groove. The knife blade stretches out of the penetration side of the groove. The distance between the edge of the knife blade and the cut support part is a little less than the thickness of a to-be-skinned cable sheath. The locking block is pressed on the knife blade. The locking block, the knife blade and the knife head are locked through locking bolt. According to the cable skinning knife, the knife blade is mounted stably and the blade can be assembled, disassembled and replaced conveniently. The cable skinning knife is applicable to cables of different diameters. The skinning depth is uniform. The cable skinning knife has the advantages of simple structure, simple and convenient operation, security, reliability and high skinning efficiency.