Hyaluronic acid (HA) is also called uronic acid. Natural hyaluronic acid is a kind of macromolecular polysaccharide, which is a linear macromolecular polysaccharide with glucuronic acid -N- glucosamine acetate as disaccharide molecular unit. Its average molecular weight is between 6,543.8+10,000 and 6,543.8+10,000 daltons, and it exists in intercellular spaces. Originally only used for moisturizing, it has been included in the ranks of wrinkle removal and plastic surgery, and it is at the forefront of biomedical beauty. This plastic technique is non-animal stable hyaluronic acid cultured by bacterial fermentation. By injecting hyaluronic acid into the wrinkled and depressed parts of the dermis or the parts that want to be full, it can play the role of wrinkle removal and face modification, and can immediately eliminate wrinkles and change appearance. Hyaluronic acid, which originally exists in the dermal tissue of human skin in the form of colloid, is responsible for storing water, increasing skin volume and making skin look full, plump and elastic. However, hyaluronic acid will disappear with the increase of age, making the skin lose its water storage capacity, gradually becoming dull, aging and forming fine wrinkles. Thanks to the progress of biotechnology, hyaluronic acid can be extracted from connective tissues of vertebrates, such as cockscomb, eyeball, umbilical cord and cartilage. In the past, hyaluronic acid was mostly extracted from animals, but now it is artificially synthesized, which avoids problems such as allergies and infections.