Objective: To investigate the characteristics of airflow in the lower airways of patient with chronic obstructive pulmonary disease under different exercise conditions using computational fluid dynamics methods. Methods: The CT scan data and pulmonary function data of patients with COPD were collected to reconstruct the real three-dimensional model of the lower respiratory tract. And the numerical simulation was performed by applying individualized boundary conditions, then we analyzed parameters such as wall pressure, wall shear stress (WSS), flow rate and pressure drop in the patients" lower airways. Results: With increasing exercise intensity, the wall pressure, WSS, flow velocity and pressure drop of lower respiratory tract in COPD patients gradually increased. The difference between the resting state and the mild exercise state was small, while the parameters of severe exercise state increased significantly. Among them, WSS was a sensitive mechanical index, and the area occupied by WSS greater than 1 Pa was 272.35 mm₂^{, 438.24 mm}₂ ^{and 4369.48 mm₂} in the three breathing states, respectively. Conclusion: The airway wall pressure, WSS, flow velocity and pressure drop of patients in exercise state are significantly increased, which increases the possibility of airway mucosal injury and inflammation. Explain the mechanism of bronchial inflammation in COPD patients and the reasons why patients cannot exercise for a long time from a mechanical point of view.