In the patients with COPD mechanical ventilation, the bronchial dilatation is very common. However, the evaluation of the efficacy of the medical examination and other subjective indicators, such as doctors, depends on the doctor's experience; at present, there is no objective evaluation index. For patients with mechanical ventilation, the risk of cross infection can not only increase the risk of cross infection, but also increase the workload of clinical doctors and nurses. Therefore, this study proposes an objective evaluation method to evaluate the response of COPD patients to bronchial dilation. The hypothesis of this study can be used to guide the clinical medication through the test of the bronchus. If the patients with bronchial dilation test positive were used in the test, the patients were not used. In this evaluation method, the changes of airway resistance were measured by the accurate measurement of the patients with inhaled bronchial dilatation.