Objective To study the application of the annular drilling in the operation of traumatic intracra-nial hematoma.Methods The clinical data of 31 cases of posterior cranial fossa hematoma were analyzed retrospec-tively.Results In 31 patients,the operation was successful and the hematoma was satisfactory.After the injury,the GOS score,22 cases recovered,8 cases of mild disability,1 case of severe disability,no case of plant survival and death.Conclusion It has high hematoma removal rate and a satisfactory recovery after surgery for traumatic posterior cranial fossa hematoma.The size and scope of the posterior fossa craniotomy are restricted by bone window, so we should have a good knowledge of the surgical indications and contraindications.