The determination of the details of the feather yarn and the count of the yarn is related to the number of finished products. It is also influenced by the number of crochet numbers. In order to hold the yarn effectively, the yarn should be 1-3 times larger than that of the core yarn. Taking 1/6.5Nm optical nylon feathers as an example, the core yarn is made of 70D/24f semi light nylon filament yarn, and the yarn is fed by two light nylon filament yarn in 75D/24f, which can ensure the quality of the yarn. In the selection of the raw material, we have made comparison and screening: the semi - extinction filament of 70D/24f, the surface of the single fiber is smooth, the fiber is easy to slip at the cutting edge when cutting, and it is not easy to cut off. The 75D/24f three leaf section optical fiber is easy to cut and has excellent optical properties, and has a large friction coefficient. It is more suitable for yarns. The fabric feels thick and durable, and the weave fabric can be made plump and erect. It has good bulking and gloss.