The clinical significance of treating the lung and intestine together in severe coronavirus disease 2019(COVID-19)was explored from the perspective of “lung and large intestine forming an exterior and interior relationship”. According to the onset characteristics and clinical symptoms of COVID-19, gastrointestinal symptoms were another major manifestations besides respiratory symptoms. The effect of simultaneous treatment of both the lung and intestine was especially significant in severe cases. Furthermore, the rationality and feasibility of simultaneous treatment of the lung and intestine for severe COVID-19 was expounded from the aspects of traditional Chinese medicine theory and modern medicine mechanism research. Representative TCM prescriptions for treating both the lung and intestines including Chenqi decoctions(Da Chenqi decoction, Xiao Chenqi decoction, Tiaowei Chenqi decoction and Xuanbai Chenqi decoction), Liangge powder and Shengjiang powder, etc., can be used in the treatment of severe COVID-19.