Atomic force microscope(AFM) is an ideal tool for detecting the fundamental interactions between bacteria and biomaterials and studying the morphology and mechanics of microsystems including oralStreptococcus mutans. In this paper, the application of AFM in study of the adhesion mechanisms and influencing factors are reviewed, which summarizes the molecular mechanism of the adhesion of oralStreptococcus mutans. Thus, it provides mechanical basis and a new way for studying bacterial adhesion.