The biopsy tissues and clinical data of patients with sexual allergic pneumonia were taken from the congressional part of the biopsied lung tissue, paraffin-embedded and HE stained. Results: 10 patients with chronic allergic pneumonia, 6 males and 4 females, aged 23-59 years, mean 47.2 years. The main manifestations were chronic cough, shortness of breath, etc. The duration of the disease ranged from 4 months to 6 years. 7 cases showed generalized interstitial pneumonia (UIP)-like fibrosis with patchy fibrosis in the lung tissue and lesions distributed along the subpleural and lobular septa, as well as peribronchial lesions. 7 cases had fibroblastic foci and visible fine bronchial hyperplasia of the peribronchial alveolar epithelium and mild fine bronchitis. Three cases had mild cellulitis. three cases had non-specific interstitial pneumonia (NSIP)-like fibrosis, which showed widening of the alveolar interrogative septum and proliferation of interstitial fibrous tissue and collagen fibers with preserved alveolar structures. With moderate-to-severe bronchiectasis, more lymphocytic infiltration was seen in the alveolar septa. Sehaumann’s vesicles were seen in one case. The UIP-like fibrosis in chronic allergic pneumonia is different from that in idiopathic UIP, except for loose granulomas and multinucleated giant cells in the interstitium. (3) The distribution of the lesions is different, as the fibrosis in idiopathic UIP is mainly distributed subpleural and along the periphery of the lobules, whereas the UIP-like fibrosis in chronic allergic pneumonia often involves both subpleural/peripheral lobules and peribronchial (central lobules). The NSIP-like interstitial fibrosis of chronic allergic pneumonia is pathomorphologically indistinguishable from idiopathic NSIP, except for the presence of loose granulomas and multinucleated giant cells in the interstitium. It is concluded that chronic allergic pneumonia can cause UIP-like or NSIP-like interstitial fibrosis. According to the current diagnostic criteria of allergic pneumonia, some patients with chronic allergic pneumonia presenting with NSIP-like interstitial fibrosis may be misdiagnosed as NSIP, which is noteworthy.