Objective]To explore the relationship between Yin-wei theory and clinical practice ,and to discuss how to apply Yin-wei theory to solve practical problems in clinical situation.[Methods]We start from the Traditional Chinese Medicine(TCM) classics Nei Jing(the Canon of Internal Medicine) and Nan Jing(Canon On Eighty-One Difficult Issues),combined with Zhang Zhongjing’s application of Guizhi decoction in his book“Treatise on Febrile and Miscellaneous Diseases”to explore the cause and effect of Yin-wei theory and to comprehensively analyze its underlying thought .[Results]We found that Guizhi decoction in the“Treatise on Febrile Diseases”was not only applied in the chapter Taiyang disease,but also involved in other four chapters of Shaoyin disease and the chapter of cholera disease.In“Synopsis of Golden Chamber”,Guizhi decoction was used to treat vomitus gravidarum and affection by cold after delivery,while in Zhongjing’s practice,Guizhi decoction derived formula was widely used in the treatment of consumptive internal injuries miscellaneous disease,indicating that many internal injuries miscellaneous diseases were closely related to external infection .Tonic medicines were rarely seen alone in classical consumptive disease treatment.[Conclusion]Practice has proven that deep learning and understanding of Yin-wei theory has great guiding significance for us to put knowledge in TCM classic theories into clinical practice .Yin-wei theory opens an important window to learn“Treatise on Febrile and Miscellaneous Diseases”and trains clinical thinking,which is worth further discussion.