Iron is a vital trace element that plays a crucial role in the growth, development, and reproduction of bacteria, such as *Bifidobacteria*. Iron deficiency or excess can negatively affect bacterial hosts. The human intestine is particularly important for maintaining body homeostasis and intestinal barrier function. Iron can influence the interaction between hosts and microorganisms by altering their growth and virulence or affecting the host's immune system. Lactic acid bacteria like *Lactobacillus acidophilus*, *Lactobacillus rhamnosus*, and *Lactobacillus casei* are reported to increase trace elements, protect the intestinal barrier, mitigate inflammation, and regulate immune function. The review focuses on the mechanisms of iron ion homeostasis in intestinal immunity and gut microbiota remodeling. Iron homeostasis is maintained by a complex network of proteins and cascades, including the hepcidin-ferroportin axis, which regulates iron absorption, storage, and release. Iron is essential for various cellular processes, such as energy production, biosynthesis, and antioxidant defense. Imbalances in iron metabolism can lead to diseases like anemia and hereditary hemochromatosis. Gut microbiota play a significant role in the initial formation and enhancement of the human immune system. They can stimulate anti-tumor immune responses and regulate CD8+ T cells, Th1 cells, and tumor-associated bone marrow cells. The composition and diversity of gut microbiota vary along the gastrointestinal tract, with the large intestine hosting the majority of microorganisms. Gut microbiota are essential for maintaining a balanced gut environment and protecting against pathogens. Iron levels can influence the structure and activity of gut microbiota. Studies show that both iron deficiency and overload can reduce the abundance of beneficial bacteria like *Lactobacillus* and increase the abundance of harmful bacteria. Short-chain fatty acids (SCFAs) produced by gut microbiota have anti-inflammatory effects and modulate the immune system, providing protection against diseases like cardiovascular disease and inflammatory bowel disease (IBD). Probiotics, such as *Lactobacillus acidophilus*, can enhance gut microbiota and improve intestinal immunity by maintaining the epithelial barrier, preventing pathogen attachment, and regulating the immune system. Prebiotics and postbiotics also contribute to gut health by promoting the growth of beneficial bacteria and strengthening the gut barrier. In conclusion, iron homeostasis, gut microbiota, and intestinal immunity are interconnected. Iron plays a critical role in maintaining internal balance and influencing gut microbiota composition, which in turn affects gut immunity and host health. Iron can also be used to induce ferroptosis, a form of iron-dependent programmed cell death, to treat cancer.Iron is a vital trace element that plays a crucial role in the growth, development, and reproduction of bacteria, such as *Bifidobacteria*. Iron deficiency or excess can negatively affect bacterial hosts. The human intestine is particularly important for maintaining body homeostasis and intestinal barrier function. Iron can influence the interaction between hosts and microorganisms by altering their growth and virulence or affecting the host's immune system. Lactic acid bacteria like *Lactobacillus acidophilus*, *Lactobacillus rhamnosus*, and *Lactobacillus casei* are reported to increase trace elements, protect the intestinal barrier, mitigate inflammation, and regulate immune function. The review focuses on the mechanisms of iron ion homeostasis in intestinal immunity and gut microbiota remodeling. Iron homeostasis is maintained by a complex network of proteins and cascades, including the hepcidin-ferroportin axis, which regulates iron absorption, storage, and release. Iron is essential for various cellular processes, such as energy production, biosynthesis, and antioxidant defense. Imbalances in iron metabolism can lead to diseases like anemia and hereditary hemochromatosis. Gut microbiota play a significant role in the initial formation and enhancement of the human immune system. They can stimulate anti-tumor immune responses and regulate CD8+ T cells, Th1 cells, and tumor-associated bone marrow cells. The composition and diversity of gut microbiota vary along the gastrointestinal tract, with the large intestine hosting the majority of microorganisms. Gut microbiota are essential for maintaining a balanced gut environment and protecting against pathogens. Iron levels can influence the structure and activity of gut microbiota. Studies show that both iron deficiency and overload can reduce the abundance of beneficial bacteria like *Lactobacillus* and increase the abundance of harmful bacteria. Short-chain fatty acids (SCFAs) produced by gut microbiota have anti-inflammatory effects and modulate the immune system, providing protection against diseases like cardiovascular disease and inflammatory bowel disease (IBD). Probiotics, such as *Lactobacillus acidophilus*, can enhance gut microbiota and improve intestinal immunity by maintaining the epithelial barrier, preventing pathogen attachment, and regulating the immune system. Prebiotics and postbiotics also contribute to gut health by promoting the growth of beneficial bacteria and strengthening the gut barrier. In conclusion, iron homeostasis, gut microbiota, and intestinal immunity are interconnected. Iron plays a critical role in maintaining internal balance and influencing gut microbiota composition, which in turn affects gut immunity and host health. Iron can also be used to induce ferroptosis, a form of iron-dependent programmed cell death, to treat cancer.