Abstract: Many Lactobacillus outer surfaces are covered with a layer of protein called surface layer proteins.Surface layer proteins can be extracted from the surface of the cells by high concentration dissociation agents such as lithium chloride, guanidine hydrochloride and urea.The isoelectric point of Lactobacillus surface layer proteins is alkaline, the molecular weight is 25-71 kDa, and the protein structure and composition are various when the source is different.The surface layer proteins of Lactobacillus have positive effects on the surface properties, gastrointestinal tolerance, adhesion and colonization of the cells.They can also assist the Lactobacillus to inhibit the infection of pathogenic bacteria and reduce the apoptosis caused by pathogenic bacteria infection.Lactobacillus surface layer proteins have unique physicochemical properties and promising probiotic functions, facilitating their wide applications in food and medicine.This review focused on the research progress of the structural properties, preparation methods, biological functions and applications of Lactobacillus surface layer proteins, and provided valuable information for further study on Lactobacillus surface layer proteins.