A 41 year-old man had suffered from cough, sputum and febrile sense for several months. On the chest CT scan, small nodules, cystic air spaces, and pneumothorax were observed. Pulmonary Langerhans cell histiocytosis was confirmed by lung biopsy. Pulmonary Langerhans cell histiocytosis in adult is an uncommon granulomatous disease of unknown cause, which affects the lung, either in isolation or in addition to other organ systems. The pulmonary symptoms at the time of presentation were nonspecific, and symptomes by the involvement of other organs ocurr sometimes. Pneumothoraces commonly were complicated the course of pulmonary Langerhans cell histiocytosis and frequently recurred. We report a pulmonary Langerhans cell histiocytosis with pneumothorax in adult.