In this paper, the properties and functions of Lactobacillus S-layer protein were reviewed. The effects of S-layer protein on surface-properties, adhesion capacities of Lactobacillus bacteria and the regulation of intestinal function are also introduced, including reducing apoptosis caused by pathogenic bacteria, immunoregulating cell activity, participating in the intestinal immune response through the interaction with SIGNR3, exerting biological function through TLRS-MyD88-NF-κB pathway and regulating expression of intestinal mucosa associated proteins. Thus demonstrated that S-layer protein plays an important role in the function of immunoregulatory effect.