Abstract: Objective To investigate the effect of ambroxol hydrochloride combined with fiberoptic bronchoscopy alveolar lavage in the elderly with severe pneumonia, and its impact on the oxygenation index, Murray lung injury score(MLIS)and metal matrix protease-9(MMP-9). Methods A total of 96 elderly patients with severe pneumonia were divided into control group and observation group according to random table method. The control group(n=46)was treated with ambroxol hydrochloride, while the observation group(n=50)was given ambroxol hydrochloride combined with fiberoptic bronchoscopy alveolar lavage. Clinical efficacy, oxygenation index and MLIS, MMP-9 of two groups were compared. Results At 1 week after treatment, the total effective rate of the observation group was significantly higher than that of the control group(P<0.05). The disappearance time of fever, cough, expectoration, lung rales and chest pain in the observation group was significantly shorter than that in the control group(P<0.05). The arterial oxygen partial pressure［p(O₂)］, - arterial oxygen saturation(SaO₂)and oxygenation index of the observation group were significantly higher than those of the control group, while the arterial carbon dioxide partial pressure ［p(CO₂)］ was lower than that of the control group(P<0.05). The scores of MLIS, CPIS and physiology and chronic health score(APACHE Ⅱ)in the observation group were lower than those in the control group(P<0.05); the levels of Toll like receptor 4(TLR4), type Ⅳ collagen(Ⅳ-C), MMP-9, C reactive protein(CRP), leukocyte count(WBC)and procalcitonin(PCT)in the observation group were lower than those in the control group, the differences were statistically significant(P<0.05). At 1 week after treatment, the lung function indexes of the two groups were higher than those before treatment, and the indexes of forced vital capacity(FVC), forced expiratory volume per second(FEV₁), FEV₁/FVC, maximum midexpiratory flow(MMF)and peak expiratory flow(PEF)of the observation group were higher than those of the control group, the differences were statistically significant(P<0.05). The incidence of adverse reactions in the observation group was lower than that in the control group, but no significant difference was found(P>0.05). Conclusion Ambroxol hydrochloride combined with fiber bronchoscopy alveolar lavage has a good clinical effect for the elderly with severe pneumonia, which can effectively improve the arterial blood gas index, reduce inflammatory reactions, improve lung function and quality of life.