Objective To investigate the prevention effect and mechanism of glucocorticoid aerosol inhalation on pulmonary infection after hepatectomy. Methods Clinical data of 66 liver cirrhosis patients complicated with primary liver cancer (liver cancer) undergoing hepatectomy in the Third Afifliated Hospital of Sun Yat-sen University between January 2013 and December 2014 were retrospectively analyzed. The informed consents of all patients were obtained and the local ethical committee approval was received. The patients were divided into the treatment group and control group according to the treatment methods. In the treatment group, 36 patients were included, 28 males and 8 females, aged from 21 to 66 years with a median age of 43 years. All patients were given with aerosol inhalation of 1 mg of budesonide (pulmicort)+30 mg of ambroxol (mucosolvan), twice daily for consecutive 6 d. In the control group, 30 patients were included, 18 males and 12 females, aged ranging from 23 to 67 years with a median age of 48 years. All cases were given with aerosol inhalation of 30 mg of ambroxol (mucosolvan), twice daily for consecutive 6 d. The changes of the arterial blood gas analysis results and X-ray radiography were observed between two groups. Arterial blood gas analysis results of two groups were compared using t test and the ratio was compared using Chi-square test. Results After aerosol inhalation, partial pressure of oxygen (PaO2) and oxygenation index (OI) in the treatment group were (116±15) and (590±42) mmHg (1 mmHg=0.133 kPa), signiifcantly higher compared with (85±17) and (452±54) mmHg before treatment( t=2. 4 2 6 , 2. 5 3 3;P<0.05). In the control group, PaO2 and OI were (101±16) and (535±50) mmHg after aerosol inhalation, signiifcantly higher compared with (86±16) and (460±56) mmHg before treatment (t=3.401, 2.440;P<0.05). In the treatment group, alveolar-arterial oxygen difference (A-aDO2) was (65±18) mmHg, significantly lower than (96±22) mmHg before treatment (t=-3.578, P<0.05). After aerosol inhalation, signiifcant differences were observed in PaO2 and A-aDO2 between the treatment group and control group (t=3.925, -6.355; P<0.05). In the treatment group, the postoperative incidence of pulmonary infection was 6%(2/36), significantly lower compared with 13%(4/30) in the control group (χ2=15.240, P<0.05). Conclusion Inhalation of glucocorticoid aerosol effectively prevents the incidence of pulmonary infection after hepatectomy probably through enhancing PaO2, improving oxygenation status of tissues and organs and increasing pulmonary ventilation function.