Abstract: There are microbes, which are planktonic and biofilms adhered on the surfaces of tube, in dental unti water lines（DUWL）, and the contaminated water source has a potential to cause a hospital infection. However, nowadays the disinfection and/or infection control of DUWL have become the routine work in either dental hospitals or clinic practice through the world. In this article, the methodology of infection control and the biological features of biofilm of DUWL were reviewed.