Abstract: Lactic acid bacteria is the predominant bacterium in the small intestine of human being and animals, which inhibit the pathogen's invasion and infection and take a great significance to maintain the balance of digestive tract. The precondition of the anti-pathogen is by mean of the mechanism that lactobacillus can bind on the surface of the intestinal tract's epithelium by their surface protein and polysaccharide, then form the predominant bacterium, which take a antagonistic action. Various factors about adhesion and the mechanism of the lactobacillus against the pathogenic bacteria were reviewed in this paper.