Half face numbness may be due to nerve dysfunction, trigeminal neuritis, cerebrovascular disease and other reasons. 1. Nerve dysfunction: Numbness of half face may be caused by nerve dysfunction due to late night, excessive anxiety, fatigue, etc. In addition, if the patient sleeps for a long time, it may also compress the facial nerve, which will lead to the symptom of numbness of half face. 2. Trigeminal neuritis: Trigeminal nerve is responsible for the sensory function of the face. If the trigeminal neuritis is caused by viral infection, numbness of half of the face may occur. 3. Cerebrovascular disease: Cerebrovascular disease, such as cerebral hemorrhage and cerebral infarction, can cause central facial paralysis, which may also cause facial numbness. It is suggested that patients should go to the hospital for a comprehensive examination to find the cause of the disease and then do the corresponding treatment.