To discuss the scientific connotation of visceral manifestation of TCM, and the role and status of the “yin-yang of the four seasons and the five viscera” theoretical holistic theory in the formation of the TCM concept of viscera, from the relationship between the lungs and the large intestine, through comparing the expression of vasoactive intestinal peptide (VIP), cholecystokinin (CCK), and substance P (SP) in lungs with jejunum, ileum, and colon tissues under different oxygenation index conditions. Methods:Twenty-seven SD female rats were divided into hyperoxia group, hypoxic group and physiological group with 9 rats in each group. The hypoxic group was given (10±1)% oxygen concentration for 8 hours per day, and the hyperoxia group was given (40±3)% oxygen concentration for 8 hours per day. Both groups were fed for 7 days. The contents of VIP, CCK and SP in lung, jejunum, ileum, and colon of rats in each group were determined by radioimmunoassay. Results:In the normal group, the expression of VIP, CCK and SP in lung was significantly different with jejunum, and no differences with ileum and colon. Hypoxia group: Compared with the lungs, the VIP and CCK in the jejunum were significantly different, but there was no difference in ileum and colon; the SP in the jejunum and ileum was significantly different, but there was no difference in colon. Hyperoxia group: compared with the lungs, VIP, SP on the jejunum had significant differences, but no differences on the ileum and colon; CCK in lung and jejunum, ileum, colon was not significantly different. The result explained that changes were related to the external environment. Conclusion:Under physiological conditions, the lung, colon, and ileum are the most closely related to each other. It can be assumed that the lung has a close relationship with the large intestine. At the same time, three brain-intestinal peptides, VIP, CCK and SP, are the material basis for the functional relationship between the lungs and the intestine. Its changes are related to the external environment, which provides a biomedical basis for the study of the theory of “yin-yang of the four seasons and the five viscera” in Huangdi Neijing of TCM.