As the product of natural macromolecule chitin deacetylating, Chitosan is linear macromolecule carbohydrate and is widely applied to medicine, chemical industry and environmental protection, etc.. The distribution, general properties and clarifying principle of chitosan, and the application of chitosan to the clarification of Chinese traditional medicine extraction are described . Compared with ethanol sedimentation process, the chitosan clarification is a safe, of innocuity, cheap and fine clarifying process. Chitosan clarification process can replace the conventional ethanol sedimentation process as the method of fining Chinese traditional medicine extraction and preparation. The feasibility and the problem are discussed. And the advice for future researching orientation is put forward.