Abstract: Vitamin A （VA） was fat-soluble and was necessary for the maintaining of normal life activity. It plays an important role in maintaining normal visual function and growth and differentiation of epithelial tissues. While VA can improve the immunity function, inhibit the growth of tumor and improve anemia, excess VA is harmful to body. The metabolism characteristics of VA and its physiological actions were introduced in this paper, so as to provide reference for the rational use of VA.