Obesity, as a global health crisis, is increasingly linked to intestinal microecology. Probiotics colonise the body, effectively regulating the balance of intestinal flora, while strengthening the intestinal barrier, activating the immune response, releasing beneficial substances, and maintaining micro-ecological balance. This process not only enhances the defence against pathogens, but also reduces the production of inflammatory factors and lowers the level of chronic inflammation. However, the specific process and mechanism by which probiotics influence the intestinal microecology through the immune response, improve metabolic disorders caused by obesity, and participate in weight management are not clear. Through multiple neural pathways including the 'gut-brain axis' and their direct interaction with the intestine, probiotics increase the number of beneficial bacteria in the intestine and inhibit the growth of harmful bacteria, thus effectively restructuring the balance of the intestinal flora. This restructuring of the balance can optimise the intestinal environment and enhance the efficiency of food digestion and nutrient absorption. Probiotics show positive effects on obesity management by regulating the metabolic process and reducing fat accumulation, providing individuals with a new way to control body weight and prevent obesity. Therefore, the application of probiotics is of great significance in promoting gut health and weight management.