The utility model relates to the technical field of mining auxiliary equipment, and discloses a mining steel wire rope tensioning device which comprises an equipment shell, three fixed pulleys are arranged in the shell, a movable pulley is further arranged between every two fixed pulleys, and the movable pulleys are arranged in a sliding way in the shell in a sliding mode. A spring device is further arranged on the side, opposite to the slideway, of the shell, and a connecting steel wire rope is arranged on a sliding seat of the spring device and connected with a frame of the movable pulley. According to the utility model, the traditional balancing weight is replaced by the spring; the size of the device is reduced, and the weight is reduced; meanwhile, the labor intensity during installation can be reduced, no noise pollution is generated, the elongation of the steel wire rope is effectively absorbed, the traction steel wire rope is prevented from slipping on a driving roller of the winch, and it is guaranteed that the endless rope continuous tractor can normally operate under the light-load or heavy-load working condition.