A-70-year-old women was admitted with open frontofacial injury by an axe. The patient's mental status was slightly drowsy and her right pupil was dilated due to direct eye injury. Brain CT showed frontofacial bone fracture, subdural hematoma and intracerebral hemorrhage in the right frontal lobe. Emergency operation including right frontal lobectomy and frontofacial reconstruction was done and patient's consciousness was completely recovered. Ten days postoperatively, acute subdural hematoma developed without head trauma. The patient expired. Authors report a case of delayed onset spontaneous acute subdural hematoma after craniocerebral injury by an axe and discussed the pathogenesis of spontaneous acute SDH with literature review.