Subdural hematoma is the accumulation of blood from intracranial hemorrhage in the subdural cavity and has the highest incidence among intracranial hematomas. According to the time of occurrence of post-injury hematoma, it is divided into acute subdural hematoma (within 3 days after injury), subacute subdural hematoma (occurring between 3 days and 3 weeks after injury) and chronic subdural hematoma (more than 3 weeks after injury). Chronic subdural hematomas are those in which blood from intracranial hemorrhage accumulates in the subdural space and becomes symptomatic more than three weeks after the injury. There is no uniform understanding of the source and pathogenesis of hematoma. The incidence of hematoma accounts for about 10% of intracranial hematomas, which often occur on the convex surface of the frontoparietal temporal hemisphere and can accumulate up to 100-300 ml of blood. The clinical manifestations are mainly increased intracranial pressure, headache is more prominent, some have mental symptoms such as dementia, apathy and mental retardation, and a few may have focal brain symptoms such as hemiplegia, aphasia and focal epilepsy. The disease manifests as a chronic process with satisfactory results if a clear diagnosis and surgery are performed in a timely manner. Those who have poor outcomes or die of the disease are mostly due to untimely diagnosis and treatment, critical condition or those with complications. How can a very simple procedure be done flawlessly? Drill the hole in the correct position and apply an orthopedic spatula after drilling to scrape away part of the inner plate of the bone hole, so that an inclined surface can appear and not insert into the brain tissue when inserting the drainage tube, but travel on the surface of the brain. Do not enter too much air after the blood is drained out leading to air cranium, inject warm saline plus close the cranium, and then release the drainage. After the operation without dehydration drugs, head high and foot low position, drainage, if the patient appears abnormal symptoms, immediate review CT. 1-2 days after drainage review CT if drainage is complete, you can remove the drainage tube.