TPU material uses the principle of gas phase differential to prepare ultra-light and highly elastic TPU foam particles. The particles expand like popcorn to 5-8 times the original volume. The particles contain a large number of microporous structures. The cells are surrounded by a large amount of air. The diameter of the cells varies from 30 microns to 300 microns. These closed cells can give the foamed particles excellent ultra-low density, high resilience and flexibility. The steam molding process is used to process about 2000 foamed particles into products of the desired shape. During this process, the outermost layer of the foamed particles melts slightly and adheres to a stable shape, while the internal pore structure is not affected. When the product is a sole, the sole can be compressed to half the size after being stressed, which greatly reduces the vibration force on the sole. After the compression force disappears, the sole can quickly rebound and return to its original shape.