Temporomandibular joint disorder is the most common disease of the oral and maxillofacial region, and the pathogenesis is not fully understood. The main clinical manifestations of this disorder are pain in the joint area, joint popping during movement, and jaw movement disorders. Most of them are joint dysfunctions with good prognosis; however, organic changes may occur in a few cases. In clinical practice, temporomandibular disorders, such as temporomandibular arthritis, disc displacement and osteoarthrosis, are the most common types of disorders that have a significant impact on human health. The theory of the protection of articular cartilage by aminoglycans has been proposed over the years to provide new ideas for the treatment of osteoarthrosis. Alterations in the intra-articular microenvironment, including biomechanical and nutritional metabolic factors, can cause degeneration of articular cartilage. The maintenance of normal structure and function of articular cartilage depends on the normal and stable morphology and metabolism of chondrocytes and matrix components, and proteoglycans play an important role in matrix metabolism, which is the most active metabolic form in cartilage. The reduced proteoglycan content and lower amino acid metabolism rate in degenerated cartilage compared to normal cartilage were also confirmed by ultrastructural observation with transmission electron microscopy. “Chitosan is chemically an amino-glucan with a structure similar to that of glycosaminoglycans (GAGS) and may be involved in proteoglycan metabolism. Intra-articular injection of rabbits with tritium-labeled chitosan solution demonstrated that exogenous chitinoglycan is involved in cartilage metabolism and can provide exogenous amino acids. Medical chitin is a kind of polyglucosaminoglycan made from chitin, a polymer compound purified from crab shells, after deN-acetylation and then deep processing, which is a medical polymer polysaccharide with good biocompatibility, biodegradability and biological activity. Its mechanism of preventing postoperative tissue adhesions are as follows: 1. Medical chitosan has the biological property of selectively promoting the growth of epithelial cells and endothelial cells and inhibiting the growth of fibroblasts, thus promoting the physiological repair of tissues, inhibiting scar formation and reducing tissue adhesions; 2. Medical chitosan has local hemostatic effect and inhibits the formation of blood fibrin bundles, thus reducing the tissue adhesions caused by the mechanization of hematoma; 3. Medical chitosan has lubricating effect and biological barrier effect, which can effectively prevent the occurrence of adhesions. The mechanism of medical chitosan to protect joint cartilage is that chitosan is physicochemically similar to intra-articular aminopolysaccharide, with viscoelasticity and slow absorption, while aminopolysaccharide is the basis of cartilage and cartilage matrix composition and metabolism. As a new type of polymeric biomaterial, because of its good histocompatibility and other biological properties, chitosan provides a new way to effectively prevent and treat TMJ diseases or reduce the degree of their lesions, and has a very high research value and application prospect.