Flax, also known as crow hemp and flax, is divided into three categories: fiber, oil, and fiber and oil, all of which are annual herbs. Due to its good hygroscopicity, fast moisture conductivity and relatively small diameter, it is one of the main fiber materials for clothes in spring and summer. Generally, the cloth woven from flax fiber is called flax fabric.

Flax fiber exists in the phloem tissue of hemp stem. After retting and degumming, part of the gum is removed, so that the adhesive fiber bundle is partially loose, and then it is processed into "beating flax", which is a process fiber composed of 10~20 single fibers.