Objective?To study the effects of tiotropium bromide combined with doxofylline on lung function and serum Matrix metalloproteinase-2(MMP-2) and Matrix metalloproteinase-9 (MMP-9) levels in patients with chronic obstructive pulmonary disease (COPD). Methods?According to the random number table method, 100 patients with COPD who were admitted to Jilin Province People's Hospital from January 2019 to January 2020 were divided into the control group and the test group, each with 50 cases. The control group was given doxofylline, and the test group was given tiotropium bromide combined with doxofylline. Both groups were treated for 4 weeks. The clinical efficacy, quality of life score, lung function and serum MMP-2, MMP-9 levels before and after treatment were compared between the two groups. Results?The total clinical effective rate of the test group was higher than that of the control group; After treatment, the levels of FEV1, FEV1?/?FVC and quality of life scores (social activities, anxiety and depression, daily life) of the two groups of patients and FVC of the test group increased, and the test group was higher than the control group; After treatment, the serum MMP-2 and MMP-9 levels of the two groups decreased, and the test group was lower than the control group (all P