Fiber linear density refers to the degree of thickness of a fiber. Fiber length refers to the length of the fiber degree. Textile fibre must have a certain degree of linear density and length to make cohesion between fiber and relies on friction force between fiber made of spun yarn. Therefore, textile fiber with a certain degree of linear density and length, which is essential for textile processing and products with a value of one. Textile processing and linear density of fibers and textiles made of silk yarn and fabric performance are closely related. Generally, lower linear density of fibers, even better, is in favour of the textile process and product quality. In the linear density of fibers influence on wearability of fabrics, fine fiber fabric made of relatively soft, luster than soft, fine fiber can be produced more light fabric, can also create permeability is good and good effect of silk-like fabric. But apt to fuzzing and pilling of fabric made of fiber, fiber fabric can be used to manufacture for stiffening, rough and rich fabrics. Similarly, the textile fiber length is also closely related to textile and product quality. Longer fiber length, length uniformity less good, short fiber content, is good for textile processing and product quality. Under the same conditions, fiber is long, high, evenness of yarn strength and yarn smooth surface, made of fabric fastness, smooth appearance, not fluff, and pilling. In addition, on the premise of yarn quality guaranteed, long fibers, the spinning of yarn, fine, more light can be used to make fabric. Statements for short, length is more important than the linear density, cotton quality and pricing of, for example, the length is the most important indicators. In the textile fibers, natural fiber linear density and length is not uniform, sometimes differences larger, as fiber varieties, varying growth conditions. And chemical fiber is made, length of the linear density of fibers and at the request of a range depending on the fiber processing and use, artificially controlled and determined.