Abstract: Objective To compare the effect of closed sputum suction method and open sputum suction method in patients with severe traumatic brain injury with mechanical ventilation. Methods Strictly according to the standard of admission, 60 patients in the intensive care unit of the Bozhou People's Hospital with severe traumatic brain injury treated by mechanical ventilation from February, 2015 to November, 2017 were selected and numbered according to the order of admission, and randomly divided into observation group with 28 cases and control group with 32 cases, using closed sputum suction method and open sputum suction method respectively in the two groups. The amplitude of pulse oxygen saturation (SPO₂) and heart rate (HR) before and after phlegm suction, number of cases of ventilator-associated pneumonia (VAP) within 1 week, duration of ventilator use, and number of deaths within 28 days were observed and recorded in the two groups. Results There was no significant difference in age distribution, male/female ratio, coma severity (Glass score), and the maximum difference of acute physiological health score (APACHE Ⅱ score) in 24 h between the two groups (P>0.05). SPO₂ decreased and heart rate increased after both methods of phlegm aspiration, but the range of oxygen saturation and heart rate fluctuation was smaller in the observation group (P<0.05). There was no statistical significance in the number of cases of VAP within 1 week, the time spent on ventilators, and the number of deaths within 28 days (P>0.05). Conclusion When the conditions permit, it is recommended to use the closed phlegm suction method for patients with severe craniocerebral injury, because the oxygen saturation and heart rate fluctuated less before and after phlegm. Application of this method may be more conducive to the prognosis of patients with severe craniocerebral injury, and is worthy of promotion.