Abstract: ［Abstract］Objective To explore the value of large dose of ambroxol hydrochloride in treating patients with acute exacerbation of chronic obstructive pulmonary disease（AECOPD）. Methods Sixty hospitalized patients with moderate-to-severe AECOPD were dived into treatment group and control group at random. The control group was given routine therapy which contained anti-inflammatory，oxygen therapy， antiasthmatic therapy and so on. The treatment group was given ambroxol hydrochloride intravenous drip therapy on basis of the routine therapy. The malonaldehyde（MDA），glutathione reductase（GSH），superoxide dismutase（SOD），FEV1%pre， dyspnea score and so on were measured before and ten days，twenty days after treatment in two groups. The outcomes of two groups were compared. Results　In the treatment group，the content of MDA of treatment after treatment ten days and twenty days was lower， the content of GSH and SOD were higher than before treatment；the content of MDA of after treatment twenty days was decreased，the content of GSH and SOD were higher than after treatment ten days， the difference had statistical significance（P＜0.05）. In the treatment group， the FEV1 % pre of after treatment ten days and twenty days were higher than before treatment，the FEV1 % pre of after treatment twenty days were higher than after treatment ten days， the difference had statistical significance（P＜0.05）. In the treatment group，the dyspnea score of after treatment ten days and twenty days was decreased than before treatment，the dyspnea score of after treatment twenty days was decreased than after treatment ten days，the difference had statistical significance（P＜0.05）.The difference of MDA，GSH，SOD，FEV1%pre between after treatment ten days and before treatment, between after treatment twenty days and before treatment, between after treatment ten days and twenty days, and the difference of dyspnea score between after treatment ten days and twenty days in the treatment group and control group all had statistical significance（P＜0.05） .Hospitalized days of the treatment group was（11.13±1.94 ）days，that of the control group was（13.50± 2.06）days， the average hospitalized days of the treatment group was shorter than the control group，the difference was statistically significance（P＜0.05）. In treatment group，only two patients had mild gastrointestinal reaction which was relieved after treatment. Conclusion Large dose of ambroxol hydrochloride can increase antioxidative ability， reduce oxidative stress degree of patients with AECOPD， meanwhile can improve patients′ pulmonary function and shorten hospitalized days.