An open-cell foam manufacturing method uses a thermoplastic elastomer material as a substrate and adds composites, foaming agents and crosslinking agents to produce a first external sheet and a second external sheet, and then forms a sandwich structure having the first external sheet, a reinforced layer and the second external sheet aligned and stacked in sequence to produce open-cell foam sheets with a sandwich structure. Threads are pressed on the surface of the foam sandwich structure by a roller to improve the slippery resistance of the foam material, which not only has high elasticity and slippery resisting property, but also creates a high tensile strength due to the fibers of the reinforced layer.