The knitted fabric containing spandex has certain internal stress formed during weaving in the inner spandex of the fibers after unloading the machine. Therefore, the purpose of preheating and shaping is to eliminate stress through the process of fabric one by one, so that the size of the fabric is fully stable, and permanent creases in the post-processing of the fabric are eliminated. If the coil formed when the cylinder is woven, the second coil is on the left side of the first coil, then the direction of the cloth should also be 7% to 10% (relative width) on the left side of the predetermined shape, so that the twist of the finished product is consistent.