We describe a 51-year-old woman who was admitted to hospital because of cough and expectoration accompanied with general fatigue and progressive dyspnea. Chest HRCT scan showed areas of ground glass attenuation, consolidation, and traction bronchiectasis in bilateral bases of lungs. BAL fluid test and transbronchial lung biopsy failed to offer insightful evidence for diagnosis. She was clinically diagnosed with acute interstitial pneumonia (AIP). Treatment with mechanical ventilation and intravenous application of methylprednisolone (80 mg/day) showed poor clinical response and thus was followed by steroid pulse therapy (500 mg/day, 3 days). However, she died of respiratory dysfunction eventually. Autopsy showed diffuse alveolar damage associated with hyaline membrane formation, pulmonary interstitial, immature collagen edema, and focal type II pneumocyte hyperplasia.