Unilateral tinnitus can be caused by a variety of reasons, and it is not possible to determine whether it is caused by a contralateral or ipsilateral brain lesion; usually both can cause unilateral tinnitus. Usually, unilateral tinnitus can be caused by secretory otitis media or sudden deafness, which is characterized by sudden hearing loss, tinnitus, ear pain, occlusion, and ear stuffiness in one ear; brain lesions (ipsilateral or contralateral) may also cause tinnitus. In addition to the above reasons, elevated blood pressure, hyperlipidemia, endocrine disorders, cerebral arterial spasm, intracranial tumors and other lesions can cause unilateral tinnitus. The causes of unilateral tinnitus are numerous, and when unilateral tinnitus occurs, patients need to go to the hospital in a timely manner for an active examination to clarify the specific causes of tinnitus, and under the guidance of the doctor for treatment.