Intestinal mucosal damage,an important reason for aggravating infection of pathogenic bacteria and destroying homeostasis.How to protect and repair damaged intestinal mucosa has gradually attracted people's attention.As the research continues,it was found that probiotics can protect the intestinal mucosa barrier through promoting the expression of tight junction proteins,increasing the secretion of mucos,inhibiting the abnormal apoptosis of intestinal epithelial cells,stimulating intestinal mucosal immune responses.In this paper,the significance of probiotics to maintain the health would be provided by expounding the structure of intestinal mucosal barrier,the damage of pathogenic bacteria to intestinal mucosa,the mechanism in the protection and repair of damaged intestinal mucosa.