The clinical feature of skin aging is the atrophy of the epidermis and dermis. Skin aging is divided into photo-aging and natural aging. Natural aging is mainly affected by genetics and metabolism, and can be protected by measures such as improving the balance of nutrition and metabolism throughout the body. The photoaging is mainly caused by sunlight and can only be prevented by avoiding sunlight and using sunscreens. There are many factors that promote skin aging, but sunlight exposure is an important reason for accelerating skin aging. Therefore, protection from the sun and ultraviolet radiation is essential for anti-aging. The water content of the skin is the main factor to keep the skin soft and elastic and prevent aging.