There is a close and profound connection between gut health and the immune system. About 70% of immune cells in the human body are concentrated in the intestinal associated lymphoid tissue. The intestine is not only an important site for digestion and absorption, but also the first line of defense against pathogen invasion. A healthy gut microbiota can maintain the integrity of the intestinal mucosal barrier, preventing harmful substances and microorganisms from leaking into the bloodstream; Meanwhile, beneficial bacterial communities can regulate the activity and balance of immune cells, promote anti-inflammatory responses, and inhibit excessive inflammation through metabolites such as short chain fatty acids. In addition, gut microbiota also participates in training and educating the immune system, helping it accurately identify "self" and "non self", thereby enhancing overall immunity. Therefore, scientific diet, regular sleep, moderate exercise, and reasonable supplementation of probiotics and dietary fiber are all important ways to maintain the balance of intestinal microbiota and support the stable operation of the immune system.