Gram-positive food-borne pathogen Listeria monocytogenes can invade non-phagocytic cells of the hosts by means of the special surface proteins and cause severe systemic infections. Internalins play a key role for Listeria monocytogenes in invading the non-phagocytic cells. In this study we will review and expand upon the recent advances in understanding the molecular mechanisms of InlA- and InlB- mediating the invasion of Listeria monocytogenes into host cells. This paper will also provide the theoretical base for pathogenetic mechanisms, precaution and therapy of food-borne pathogens.