Abstract: Obj ective To observe and analyze the curative effect of N-acetylcysteine (NAC) on adj uvant treatment of the patients with acute exacerbation of chronic obstructive pulmonary dis-ease (AECOPD)and its influence on oxidative stress and pulmonary function.Methods 100 AE-COPD patients were selected as the research obj ects and randomly divided into the observation group and the control group,50 cases in each group.The patients in the two groups were treated with the conventional treatment,and the patients in the observation group were treated with the oral NAC treatment on the basis of the conventional treatment.The curative effect of the patients was evaluat-ed according to the change of the clinical symptoms before and after the treatment,the pulmonary function indexes of forced expiratory volume in one second (FEV1 ),the first second forced respira-tory volume ratio of forced vital capacity (FEV1/FEC%)and FEV1 percentage of the patients in the two groups before and after the treatment were detected.The anti oxidative stress indexes of glu-tathione transferase (GSH-ST)activity,inhibition of hydroxyl radicals and the ability of anti super-oxide anion free radicals in serum specimens of the patients were detected.Results After the treat-ment, the clinical efficacy of the two groups were 94% and 72%, the clinical efficacy of the observation group was significantly higher than that of the control group (P<0 .0 5 ).The proportion of the patients with the curative effect of“significant ”in the observation group was significantly higher than that of the control group (PP<0 .05 ),and the proportion of the pa-tients with the curative effect of“effective”or“invalid”in the observation group was significantly lower than that of the control group (P<0 .05 ).The pulmonary function indexes of the patients in the two groups significantly improved (P<0 .05 ),and the pulmonary function indexes of the patients in the observation group were significantly higher than those of the control group (P <0 .05 ).The anti oxidative stress indexes of the patients in the two groups significantly improved (P<0 .05 ),and anti oxidative stress indexes of the patients in the observation group were signif-icantly higher than those of the control group (P<0 .05 ).Conclusion Application of NAC in adjuvant treatment of AECOPD can achieve significant curative effect,improve the lung function of patients significantly and alleviate the oxidative stress of the patients.