ObjectiveTo evaluate the effect of traditional Chinese medicine sputum discharge liquid on preventing ventilatorassociated pneumonia(VAP). MethodsA randomized doubleblind, placebocontrolled study  was conducted, according to the inclusion and exclusion criteria, patients with respiratory failure and mechanical ventilation in the intensive care unit (ICU) of a hospital in 2011-2014 were selected and divided into treatment group and control group. Treatment group received sputum discharge liquid in addition to conventional treatment, control group adopted simulation agent based on conventional treatment. The incidence, treatment effectiveness, occurrence time, and prognosis of VAP between two groups of patients were compared. ResultsA total of 139 patients were monitored, 70 cases in treatment group and 69 in control group.  The incidence of VAP in treatment group and control group were  37.14% (n=26) and 57.97％(n=40) respectively; the average onset time of VAP in treatment group and control group were (76±3.2）hours  and （45±8.9）hours after admission to ICU respectively; treatment effectiveness rates in treatment and control group were 88.46% and 55.00% respectively; the incidence, occurrence time,and treatment effectiveness rates of VAP between two groups of patients were both significantly different (all P<0.05). There were no significant difference in blood routine, liver and kidney function, urine routine, stool routine, and  electrocardiogram results between two groups of patients (all P>0.05). ConclusionIntervention in patients with mechanical ventilation by sputum discharge liquid can reduce the incidence of VAP, and has a positive effect on the prognosis of disease and pulmonary infection in patients.