Subdural fluid in the frontal area on both sides is mostly seen in the elderly. The gap between brain tissue and dura mater increases after brain atrophy in the elderly, and the increased gap is filled with cerebrospinal fluid to form subdural fluid, which is not too much and does not cause obvious clinical symptoms. Most people find it unintentionally, so there is no need for special treatment, and it can be observed, and the amount of fluid can be reviewed periodically by CT or MRI. If the amount of fluid accumulation is found to be gradually increasing, producing a significant occupying effect or if the subdural fluid accumulation turns into a subdural hematoma, then surgical treatment is required and a borehole drainage can be performed.