Influenza is one of the major public health diseases that human beings are facing, and there is no better way to treat influenza except western medicines antiviral and symptomatic treatment. Ancient Chinese medicine has accumulated a lot of experience in the prevention and control of influenza, which deserves our reference. However, due to the different diagnosis of Chinese and western medicine, plenty of ancient experience of cannot be directly used. Based on traditional syndrome differentiation theory of external contraction in TCM, this article discussed the attribute of influenza in Chinese medicine, hoping to promote the flexible application of ancient TCM syndrome differentiation and treatment experience of external contraction in the prevention and treatment of influenza.