Abstract: Objective To analyze the application value of pathological diagnosis in analyzing the reason of death in a case of Methods ， ， occupationalpneumoconiosis. Theoccupationhistory occupationalexposurehistory clinicaldataandpathological - Results data of a dead patient with occupational pneumoconiosis were retrospectively analyzed. The patient was exposed to ， inorganic dust for more than ten years in a private factory. In January 2019 the computed tomography showed diffuse nodular mass with dense shadows in both lungs and left pneumothorax. He was admitted to a number of hospitals and the clinical diagnosis suspected that he suffers from occupational pneumoconiosis. He eventual died of bilateral pneumothorax in a local hospital in December 2020. The forensic identification of the cause of death confirmed that the lungs of the deceased had ， pathologicalchangesconsistentwithoccupationalpneumoconiosisstage Ⅱ secondarybilateralspontaneouspneumothoraxand （ ）， bilateral pleural effusion significant on the left side and the primary cause of death was severe lung disease. According to GBZ 25-2014 Pathological Diagnosis Criteria of Pneumoconiosis，the medical examiner diagnosed that the deceased had （ ） Conclusion suffered from pneumoconiosis before death pneumoconiosis stage Ⅱ . Pathological diagnosis can provide ， objectiveevidenceforthediagnosis differentialdiagnosisandcauseofdeathduetopneumoconiosis.