Twisting is to make the two sections of the sliver rotate relatively, at this time, the fibers in the sliver that were originally parallel to the yarn axis are inclined into a helix. For short fibers, twisting is mainly to improve the strength of the yarn. The twisting of filament can not only improve the strength of yarn, but also produce some effects. The amount of yarn twist and the matching of yarn twist direction and twist in fabric have great influence on the appearance and performance of products.