ObjectiveTo retrospectively analyze the clinical,pathological and imaging features of one case pathologically diagnosed as cryptogenic organizing pneumonia(COP) to improve clinical diagnosis and treatment. MethodsWith a case report and review of the related literatures,the clinical manifestations,radiological features,pathological features,differential diagnosis,management and prognosis of COP were discussed. ResultsThe clinical manifestations of COP had no specificity. The imaging manifestations were real shadows,ground glass shadows,nodules and all kinds of tape. Pathological features of lung specimen biopsy showed buds of granulation tissue within alveolar ducts and alveoli consisting of fibroblasts. Remarkable response to corticosteroids was found in this patient. The prognosis of COP was good. ConclusionsCOP is diagnosed on basis of clinical,pathologic,and imaging findings. The radiological features of COP which show mass with cavity are rare. It can be easy misdiagnosed as lung infection or tumor. The effects of ordinary anti-bacteria therapy are limited,while the corticosteroids therapy shows preferable effects. Therefore,it's important to acquire pathological evidences as early as possible to guide the diagnose and treatment.