Abstract： Objective To discuss the effective oral nursing methods of critically ill patients with orotracheal intubatton in order to reduce oral infection,reduce oral colonization,cut off the stomach-oral-pulmonary infection route,and reduce the number of ventilator-associated pneumonia.Methods Research methods for prospective cohort study.According to the random number will be subject,the cases were divided into experimental group and control group.Experimental group was given 2.5% sodium bicarbonate solution line cleaning,washing and rinsing the oral cavity,three times a day.The control group was given normal saline line cleaning,washing,cotton mouth.Two groups were made at the oral care before and after determination of the pH value after 48 hours.Sicksinus sputum culture and oral monitoring colonization were analyzed of two sets of ventilator-associated pneumonia (VAP) incidence..Results The incidence of ventilator-associated pneumonia in experimental group was reduced (P<0.05>,and the fungal infection rate was significantly decreased..Conclusions With 2.5% sodium bicarbonate solution line of oral rinse can effectively reduce oral colonization and decrease the incidence of ventilator-associated pneumonia.