Chronic obstructive pulmonary disease (COPD) is a common chronic airflow obstructive disease. Patients with chronic obstructive pulmonary disease have increased airway mucus secretion with impaired mucus clearance and the same conditions as asthma for Aspergillus airway colonization. Some studies have shown that the positive rate of Aspergillus fumigatus culture in the airways of patients with chronic obstructive pulmonary disease can reach 37%, and 13% of patients with chronic obstructive pulmonary disease were found to have Aspergillus fumigatus sensitization through skin prick test (SPT) of Aspergillus antigen and serum specific IgE assay, and these Aspergillus fumigatus sensitized patients with chronic obstructive pulmonary disease have worse lung function status. In recent years, the foreign literature has seen individual reports of ABPA in patients with slow-onset lung disease, but this has not been reported in the domestic literature. In our clinical work, we have diagnosed 3 cases of ABPA in combination with slow-onset lung, which are reported and analyzed here to improve the understanding and management of this rare clinical condition. All three cases had a history of bronchiectasis, asthma, rhinitis, sinusitis, eczema and other allergic diseases, and family history of asthma. Pulmonary function changes were in accordance with the diagnostic criteria of chronic obstructive pulmonary disease. All 3 patients met the criteria of positive rapid response to Aspergillus SPT, serum total IgE >1000 IU/mL, previous infiltrative shadows in the lungs, peripheral blood eosinophil ratio >5%; serum Aspergillus-specific IgE was increased (>0.35 KU/L) and serum Aspergillus-specific IgG was increased (>40 mg/L); HRCT showed central bronchodilation in all 3 cases, HRCT The visual score of bronchodilatation was 7.0-9.5, suggesting mild or moderate bronchodilatation; two cases had coughed up brown sputum clots, and one case had positive sputum culture for Aspergillus fumigatus. All three patients were treated with oral prednisone (0.5 mg/kg-1/d-1) for 2 weeks on the basis of chronic obstructive pulmonary therapy, after which the dose was gradually reduced and maintained, and case 2 was treated with intravenous itraconazole for 10 days. all three cases had improvement in symptoms after 2 weeks of treatment, dyspnea was significantly reduced, serum total IgE and Aspergillus-specific IgE were reduced, and lung function improved to different degrees in all three cases. Discussion】 To achieve early recognition of COPD combined with ABPA clinically, we should first ask for detailed medical history, whether there are recurrent wheezing episodes, or recurrent acute exacerbations even after treatment with inhaled long-acting bronchodilators/inhaled corticosteroids for COPD. Peripheral blood eosinophil count and serum total IgE assay are simple and easy screening tools. Aspergillus antigen skin tests and serum Aspergillus-specific IgE and IgG assays are necessary to confirm the diagnosis of ABPA. It should be noted that in elderly people, especially in COPD patients, the positive rate of SPT will be reduced due to skin laxity, and intradermal tests for Aspergillus antigen can be taken if necessary. Since 24% of ABPA has no imaging manifestations of bronchiectasis, attention should be paid to the diagnosis of serotype ABPA. It is important to note that the diagnosis of COPD combined with ABPA requires clinical compliance with the diagnostic criteria for both diseases. Therefore, when considering COPD combined with ABPA, it is particularly important to have adequate diagnostic criteria for COPD, such as a history of smoking or A history of exposure to other COPD risk factors is required. Although pulmonary HRCT is not necessary for the diagnosis of COPD, HRCT demonstrating emphysema in this setting is an important piece of evidence for the diagnosis of COPD. Systemic corticosteroids are the basic treatment for ABPA, and inhaled corticosteroids (even at high doses) are largely ineffective. Our three patients with COPD combined with ABPA had different remissions after oral prednisone treatment, with reduced total serum IgE and trichothecene specific IgE and some improvement in FEV1%. Since systemic corticosteroids are not recommended for the treatment of stable COPD, the diagnosis of combined ABPA has positive therapeutic implications because long-term systemic corticosteroid therapy for ABPA not only controls the overall disease but also prevents further structural lung destruction and pulmonary function impairment based on COPD.