Wool is mainly composed of protein. The use of wool can be traced back to the Neolithic age, spread from Central Asia to the Mediterranean and other parts of the world. Wool became the main textile raw materials in Asia and Europe. Wool fiber is soft and elastic; it can be used for the production of wool fabric, wool yarn, blanket and other textiles. Wool products have the features of full handle, good warmth retention and comfortable wearing. Sheep wool accounts for a considerable proportion of textile materials. Australia, the former Soviet Union, New Zealand, Argentina, China, etc., have larger wool output in the world. Sheep wool is divided into 5 types: fine wool, semi fine wool, long wool, hybrid wool and coarse wool according to fineness and length. Chinese wool breeds include Mongolian wool, Tibetan wool and Kazakh wool. The main factors to evaluate wool quality are fineness, crimp, color, and strength and grass impurity content.