The invention discloses a releasing device for a power cable. The releasing device comprises a rack. The rack comprises two cross beams. One end of one cross beam is connected with one end of the other one cross beam through a cutting table. Supporting legs are arranged at the two ends of each cross beam. The inner side of each cross beam is connected with a supporting frame. A hydraulic cylinder is arranged on each supporting frame. A lifting rod is arranged at the upper end of each hydraulic cylinder. A supporting shaft used for lifting a cable reel is arranged between the two lifting rods. The end parts of the supporting shaft are connected with the lifting rods. A wire groove is formed in the upper end face of a cutting table. A pressing plate is arranged on the wire groove. The pressing plate is connected with the cutting table through a bolt. A cutter is arranged on one side of the cutting table. One end of the cutter is rotationally connected with the cutting table. A first wire pressing device and a second wire pressing device are arranged between the cutting table and the supporting frame. The first wire pressing device and the second wire pressing device are both connected with the rack. The first wire pressing device and the second wire pressing device are oppositely arranged. A power cable penetrates through the position between the first wire pressing device and the second wire pressing device.