Abstract: Objective: To study CT precancerosis and the value of follow-up CT scan for promptly disclosing delayed intracranial hematoma due to trauma. Methods: Follow-up CT scan was Performed in 120 patient with head injury. Results: On re-examination CT scan. 32 delayed intracranial hematoma were discovered. Among them, extradural hematoma was found in 16 cases. subdural hematoma in 12 cases and inttacerebral hematoma in 4 cases. About 80% of delayed hematomas occur within 3 days after trauma.Conclusion:Most of Delayed intracranial hematomas can be demonstrated on CT scan within 3 days after trauma. It is suggested that although the initial CT scan was normal, an immediate repetition of CT examination is indicated whenever patients show deterioration of cliaical symptoms and signs.