Pall ring packing is formed by opening eight layers of small rectangular windows on the wall of the ordinary Raschig ring. The small window blades overlap in the center of the ring, and the upper and lower layers overlap each other. The main difference between it and the Raschig ring packing is that there are rectangular window holes on the side wall, and the window blades of the window holes are bent into the ring center. Due to the opening of the ring wall, the gas and liquid distribution performance is larger than that of the Raschig ring. The improvement, especially the inner surface area of the ring can be fully utilized.