Lactic acid bacteria are commonly used in fermented foods， which play important roles in different activities， such as maintaining the micro-ecological balance， regulating the host immunity and preventing or treating diseases as probiotics. Surface layer protein (SLP) is the major adhesin on the surface of lactic acid bacteria， which plays a significant role in the relationship between bacterial phases and microenvironment. In this paper， SLP of lactic acid bacteria was explored and its functions were summarized， focusing on the effects of support and protection on bacterial cells； recognition and adhesion to the cells； inhibition of pathogen invasion； and host immunoregulation. In addition， the application of SLP in biotechnology， nanotechnology and vaccine research were elaborated in order to provide a basis for further research and development.