Maifan stone is a kind of mineral medicine in Chinese medicine, which has good adsorption, dissolution, mineralization and biological activity. It has an excellent therapeutic effect on livestock, poultry and aquatic animals suffering from intestinal diseases. This study explored the effect of Maifan stone on the growth ability of Lacticaseibacillus rhamnosus GG (L. rhamnosus GG) and the effect of Maifan stone‐L. rhamnosus GG‐fermented product on the intestinal inflammation and gut microbiota. We find that Maifan stone can adsorb L. rhamnosus GG to form a carrier bacteria. Maifan stone has the characteristics of acid tolerance and bile salt tolerance and can also improve the activity of L. rhamnosus GG in artificial gastrointestinal juice. The fermented product can reduce the degree of diarrhoea and colon pathology in rats to a certain extent and significantly improve intestinal inflammatory factors and gut microbiota. This study improves the application effect of L. rhamnosus GG in the prevention and treatment of diarrhoea animals and provides a scientific basis for the rational development of Maifan stone resources. Significance and Impact of the Study: This study explored the influence of Maifan stone‐Lacticaseibacillus rhamnosus GG‐fermented product in rats with diarrhoea. We found that Maifan stone and the fermented product can reduce the degree of colon pathology in rats to a certain extent, and significantly improve intestinal inflammatory factors and gut microbiota. Therefore, we can reasonably infer that the fermented products are expected to be developed as feed additives, which can replace antibiotics to prevent and treat livestock and poultry intestinal diseases, improve their resistance, reduce feed coefficient, increase feed conversion ratio and improve production performance.