Chronic obstructive pulmonary disease (COPD) can be graded according to clinical FEV1/FVC, FEV1% predicted value and symptoms, which are categorized into five grades from 0 to 4. FEV1/FVC is the proportion of the exhaled gas volume in the first second of forceful inhalation and then forceful exhalation to the current exhalation volume, which can show whether there is a dysfunction in the ventilation function, and the FEV1% predicted value is the percentage of the first-second forceful exhalation volume to the predicted value, and it is also an important indicator to reflect the lung ventilation function. Grade 0: The patient is at high risk for COPD, which is the mildest form of COPD, with normal lung function and only risk factors for COPD (smoking, occupational dust and chemicals, infections, etc.). Grade 1: The patient has mild COPD at this point, with FEV1/FVC ≥ 80% of predicted values. Patients may have symptoms of chronic cough and sputum, of course, some patients do not have symptoms, when there is no symptom does not need special treatment, pay attention to prevention can be. Grade 2: The patient has moderate COPD at this time, 50% ≤ FEV1/FVC<70% of the expected value. At this time, the patient will have chronic cough and sputum symptoms, the more serious patients will also be accompanied by dyspnea. Grade 3: The patient has severe COPD, 30% ≤ FEV1/FVC<50% of the expected value. This is also the most severe form of COPD, with respiratory failure or right heart failure. Grade 4: The patient has very severe COPD at this time with FEV1/FVC<30% predicted. This period is characterized by severe airflow limitation or chronic respiratory failure, and quality of life is considerably affected, when acute exacerbations can be life-threatening. If you want to determine whether you are suffering from COPD and its grade, it is recommended that you go to a regular hospital to have the relevant tests performed and then diagnosed by a doctor.