This study explored the interaction mechanism between the respiratory system and the digestive system, revealing the multi-level synergistic effect of the two systems in human physiological activities. The respiratory system mainly provides oxygen support to the body through gas exchange and maintains acid-base balance by excreting carbon dioxide; the digestive system is responsible for the absorption of nutrients and the excretion of metabolites to meet the body's energy and nutritional needs. The two systems work together in multiple regulatory pathways such as the nervous, endocrine and blood circulation to achieve physiological complementarity and dynamic balance. This study verified the bidirectional regulatory effects of the sympathetic and parasympathetic nerves on respiration and digestion under stress and rest, and the mutual support of the two systems in acid-base balance and metabolite processing through preliminary data. The results provide a theoretical basis for further understanding the mutual regulation between the respiratory and digestive systems, and have reference value for related clinical interventions.