Ventilator-associated pneumonia (VAP) is commonly severe, and associated with high health care costs. After endotracheal intubation, endotracheal tube (ETT) provides an ideal surface for bacterial adhesion and proliferation, which then leads to parenchymal lung infection. The growth of biofilm on the inner lumen of the ETT is the main cause of VAP. This article introduced the factors affecting the formation and development of ETT biofilms and their roles in the treatment of VAP.