Abstract: The structure analyses of negative Poisson’s ratio foam and polymer show that the negative Poisson?s ratio materials have microstructures with re-entrant and internal rotation folded structure, which is the essence for auxetic effects and the design concept of auxetic textile materials. The investigation on the structure of auxetic fiber, yarn and fabric, also demonstrates that re-entrant structure or internal-rotation folded structure is the basic structure for auxetic fiber, internal-rotation folded structure being the basic structure for auxetic yarn, and re-entrant structure or internal-rotation folded structure being the basic structure for auxetic fabric. The present work of the structure and development trend of negative Poisson's ratio material can contribute to improve the new textile material technology and new functional textile products.