The autopsy can offer great help for confirming the exact reason about the death on co-existence of postmortem injury and disease. The case reported here is just an appropriate illustration on the above viewpoint. The deceased, having suffered from the coagulation dysfunction when lived, died several days after tussling with her male-friend. Autopsy found the extensive subcutaneous bleeding and retroperitoneal hematoma in the lower part of her abdominal cavity and that of the pelvic. But the further examination showed no damage of the peritoneal organs inside her abdominal and pelvic cavity. The source of bleeding was finally discovered based on the anatomic knowledge of those relevant human corporal regions, and the cause of hemorrhage was determined. With comprehensive analysis of the case and autopsy results, the deceased was ascertained of dying from the hemorrhagic shock caused by the massive internal bleeding over coagulation dysfunction, and the tussling only an incentive effect.