Abstract: OBJECTIVE To explore the CT findings of the elderly patients with pulmonary aspergillosis and distinguish it from bacterial pneumonia. METHODS A total of 29 elderly patients with pulmonary aspergillosis who were hospitalized in the Tianjin Fifth Central Hospital from Jan 2017 to Dec 2020 were assigned as the pulmonary aspergillosis, meanwhile, 42 elderly patients with simple bacterial pneumonia were assigned as the bacterial pneumoniae group. The clinical symptoms and CT signs were compared between the two groups. Taking the final confirmed results as the golden standard, Kappa consistency test was used to evaluate the efficacy of CT in differential diagnosis of pulmonary Aspergillus infection. RESULTS Cough and expectoration, fever, chest tightness or chest pain, hemoptysis, polypnea and dyspnea were the major clinical symptoms of the two groups of patients; the number of cases of fever was significantly less in the pulmonary aspergillosis group than in the bacterial pneumonia group（P＜0.05）; there was no significant difference in the number of cases of other symptoms between the two groups. Among the CT signs, the proportions of the patients who had large nodules, lumps, tree-in-bud pattern, halo signs, air meniscus sign and cavities were significantly higher in the pulmonary aspergillosis group than in the bacterial pneumonia group（P＜0.05）; the proportions of the patients who had consolidation and air bronchial signs were significantly lower in the pulmonary aspergillosis group than in the bacterial pneumonia group（P＜0.05）. The differential diagnosis with CT was highly consistent with the confirmed results（Kappa value=0.543）, and the sensitivity, specificity and accuracy were respectively 79.31%, 76.19% and 77.46%. There was no significant difference in the area under curve（AUC） of receiver operation characteristic among the chest CT examination, sputum culture and blood culture. CONCLUSION The elderly patients with pulmonary aspergillosis show diversified CT findings; tree-in-bud pattern, halo signs, air meniscus sign and cavities may facilitate the diagnosis and differential diagnosis of the pulmonary aspergillosis.