Objective In order to explore the characteristics of airway resistance after treatment in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), a total of 50 patients between March 2017 and March 2018 to the hospital respiratory medicine clinics because of AECOPD were selected, including 39 males and 11 females, mean age (68.1± 8.7)years. All of the patients were performed routine SPulmonary function test (PFT) combined with impulse oscillation (IOS) before the first day and after the seventh day of the ambulatory treatment, and the changes of parameters were compared. After treatment, Fres, R5, R20, R5-R20, X5 and AX were significantly lower than those before treatment. R5-R20 had the most obvious negative correlation with FEV1/pred (r=-0.507, P<0.05), while there was no statistically significant correlation between R20 and baseline PFT (P>0.05). The results show that the total airway viscosity resistance decreased after treatment in AECOPD patients. R5-R20 is most correlated with baseline PFT. The more severe the airflow limitation is, the more significant the improvement of peripheral airway viscosity resistance will be. R5-R20 has relatively reliable clinical applicability as an evaluation index for the treatment effect of acute exacerbation of COPD.