The invention discloses a high-efficiency auxiliary welding device for new energy transportation pipelines. Lifting devices are located at bottoms of welded positions of the pipelines; sliding devices are located at lower parts of the pipelines; each lifting device comprises a hydraulic jack, a supporting rod and a bracket; each sliding device comprises pulleys, rotating rollers, rolling wheels, connecting rods and supporting seats; limiting holes are formed in surfaces of rod bodies of the connecting rods; fixing rods are inserted in the limiting holes; the connecting rods are arranged on upper surfaces of the supporting seats; bottom ends of the connecting rods are inserted into the supporting seats; and a cooling device comprises mist spray heads, a water pump, a pipeline and a running water pipe. With the high-efficiency auxiliary welding device, the lifting devices provided with the hydraulic jacks are added, the manpower is saved, and the operation is more convenient; the sliding devices provided with the pulleys are added, and the trouble of machine hoisting is avoided; and the cooling device sprays cooling water through the mist spray heads, the time required for cooling work is shortened, and the welding work efficiency is further improved.