〔Abstract〕 Objective To investigate the effect of different doses of ambroxol hydrochloride in the treatment of elderly patients with ventilator-associated pneumonia (VAP). Methods A total of 60 patients with VAP admitted to The Third People's Hospital of Hechi City from June 2016 to June 2020 were randomly divided into observation group and control group, with 30 patients in each group. The control group was given 30 mg ambroxol hydrochloride and the observation group was given 300 mg ambroxol hydrochloride. The clinical efficacy, bacterial clearance rate, intensive care unit (ICU) stay, mechanical ventilation duration, inflammatory indexes [clinical pulmonary infection score (CPIS), C-reactive protein (CRP), procalcitonin (PCT)] and adverse reactions were compared between the two groups. Results The total effective rate in the observation group was 93.33%, significantly higher than 73.33% in the control group, and the difference was statistically significant (P < 0.05). The bacterial clearance rate of the observation group was 53.33%, which was significantly higher than 26.67% of the control group, and the difference was statistically significant (P < 0.05). The length of ICU stay and mechanical ventilation time in the observation group were significantly shorter than those in the control group, with statistical significance (P < 0.05). After treatment, the levels of CPIS, CRP and PCT in the observation group were significantly lower than those in the control group, with statistical significances (P < 0.05). There was no significant difference in the incidence of adverse reactions between the observation group (16.67%) and the control group (20.00%) (P > 0.05). Conclusion The efficacy of high dose ambroxol hydrochloride in the treatment of elderly patients with VAP is better than conventional dose, which can effectively control infection and improve clinical prognosis.