A total of 26 patients with myositis/dermatomyositis with pulmonary involvement, of whom 6 underwent autopsy, 5 underwent open lung biopsy or transthoracoscopic lung biopsy, and 15 underwent percutaneous lung biopsy for comprehensive clinical, imaging, and pathological and prognostic analysis. Results The median age of the 26 patients was 48 years (19-65 years), 10 men and 16 women. Chest x-ray mainly showed ground glass-like changes with patchy shadows and grid shadows in both lungs. Pathological manifestations were diffuse alveolar injury (DAD) in 5 cases; lymphocytic interstitial pneumonia in 2 cases; nonspecific interstitial pneumonia (NsIP) cell-rich type in 6 cases and mixed type in 8 cases; mechanized pneumonia in 4 cases; and common interstitial pneumonia (uIP) in 1 case. All patients were treated with prednisone + cyclophosphamide. The median follow-up was 15 months (6-108 months), and the median survival was 21 months (1-253 months). 18 of 26 patients improved or stabilized, and 8 died, of whom 5 had pathologic manifestations of DAD, 2 had mixed NsIP, and 1 had uIP. conclusion Patients with polymyositis/dermatomyositis with pulmonary involvement have diverse chest cT and pathologic manifestations, and pathologic diagnosis of The prognosis of those with DAD is poor.