Stretch fabrics are wide-spread for high performance clothing use with requirements of fitness and adaptability to humans movement. A newly developed 100% PET high stretch fabric has excellent properties with respect to stretch, softness, bulkiness, and apparent volume compared to PET filament fabrics. The 100% PET high stretch fabric shows advantages of a dimensional stability, dye and agent adaptability in dying and finishing process, a property of stretch recovery after washing and lower production cost than that of spandex fabric. KES-FB was used to measure mechanical properties to various directions of the fabric. This study centered on whether the 100% PET high stretch fabric is suitable to quality and shape retention of fabric by testing several properties including tensile, compression, shear, bending and surface characteristic to various measuring directions. Tensile linearity showed maximum value at 0°in plain and 90°in twill. Shear Stiffness of plain and twill showed maximum value equally at 45°and 135°. Bending rigidity showed maximum value at 0°in plain and 45°twill. Mean deviation of MIU showed maximum value at 0°and 90°in plain and 135°in twill.