人体内肠道菌群数量庞大，功能复杂，在促进食物消化吸收、免疫调节、物质代谢、维护机体健康和疾病的防控方面发挥重要作用。儿童属特殊群体，由于其肠道发育不完善，肠道菌群容易受分娩方式、喂养方式、抗生素应用等多种外部因素的影响。肠道菌群的紊乱会阻碍肠道功能的发挥，引起儿童营养不良甚至疾病的发生。此综述主要关注近年临床上儿童难治性消化系统疾病肠道菌群的变化，总结肠道菌群参与调节肠道免疫反应的机制，以及肠道菌群之间制约消长的关系，以寻找调节免疫反应的有益菌株。“,”Intestinal microflora in human body has a large number and complex functions. It plays an important role in promoting food digestion and absorption, immune regulation, material metabolism, maintaining body health and disease prevention. Due to the immature intestine in children, the diversity and abundance of intestinal flora are easily affected by many external factors, such as delivery mode, feeding mode and antibiotic application. The disorder of intestinal flora will hinder the development of intestinal function and cause malnutrition and even diseases in children. This review focuses on the changes of the intestinal flora in children with refractory digestive diseases in recent years. It summarized the mechanism of intestinal flora involved in the regulation of intestinal immune response, and the relationship between intestinal flora restricting growth and decline, so as to find beneficial strains to regulate immune response.