A thermoplastic polyurethane (TPU) foam product with high flatness, and a preparation method and a use thereof are provided. The TPU foam product is prepared by processing aliphatic thermoplastic polyurethane (ATPU) beads with a melting range of 20° C. to 50° C. and a melting point of 90° C. to 160° C. by a physical gas foaming process to obtain foamed ATPU beads and heating the foamed ATPU beads with a heat source to make the foamed ATPU beads fused. The TPU foam product with high flatness has a density of 0.08 g/cm3 to 0.8 g/cm3 and a flatness value of less than 2 mm, and the flatness value is determined by a fixed-length ruler. The TPU foam product not only has high flatness such that diversified designs are allowed for a surface of the product, but also has high resilience.