Tinnitus is a common symptom that produces abnormal sound sensations unrelated to external stimuli and manifests auditory dysfunction. And feeling a sound in the skull is cranial/cephalic tinnitus. The pathogenesis of tinnitus is complex and may be related to fatigue, sleep, menstrual cycle, emotional factors, inflammation, trauma, tumors, hormones and neurotransmitters, the state of blood circulation in the head and ischemia and hypoxia in the inner ear. The majority of tinnitus is subjective tinnitus, i.e., spontaneous tinnitus, which can only be heard by the patient himself; a few are objective tinnitus, i.e., other-perceived tinnitus, which can be heard by both the patient and the examiner. The common causes of other-perceived tinnitus are: (a) Vascular tinnitus: such as carotid bulla, jugular vein bulla, aneurysm, arteriosclerosis, inflammatory sarcoidosis of the middle ear, vascular sounds heard due to head and neck vascular lesions. (ii) Muscular tinnitus: sounds heard due to contraction of the occlusal muscle, pterygoid muscle, tympanic membrane tensor, stapedius muscle, and eustachian tube muscle. (iii) Open eustachian tube tinnitus: abnormal opening of the eustachian tube, which can be heard when swallowing or yawning. (b) Self-perceived tinnitus: According to the symptoms, it can be divided into pure tone tinnitus and noise tinnitus; there are single tinnitus and double tinnitus; there are intermittent tinnitus and persistent tinnitus; according to the location of the lesion, it can be divided into auditory tinnitus caused by lesions of the auditory system and non-auditory tinnitus caused by lesions of sensory systems other than the auditory system. Auditory tinnitus can be divided into: (a) external tinnitus: such as inflammation of the external ear canal, foreign bodies, cerumen, and external ear tumors; (b) middle ear tinnitus: lesions such as inflammation of the tympanic membrane, trauma, acute and chronic suppurative otitis media, exudative otitis media, middle ear tuberculosis, trauma, and tumors; (c) cochlear tinnitus: lesions due to external hair cell lesions, neuropathy, vascular striae, and physical/chemical abnormalities of the inner ear fluid. (iv) Auditory neural tinnitus: auditory neuroma can be seen as auditory neural tinnitus, due to brain tumors and vascular lesions including central auditory tinnitus of the brainstem. Non-auditory tinnitus can be caused by concussion, temporomandibular joint syndrome, cardiovascular system lesions (hypertension/low blood pressure, atherosclerosis, etc.), hematologic diseases (e.g., anemia, etc.), hepatic encephalopathy, cervical spondylosis, central nervous system diseases (e.g., multiple sclerosis, etc.) There are many diseases that cause tinnitus, therefore, for tinnitus, detailed medical history, symptoms, physical examination (such as ear, nose, throat, head and neck, blood pressure, etc.) and selective auxiliary examinations (such as tuning fork test, electrical response audiometry, tinnitus matching, acoustic impedance, auditory brainstem evoked potentials, blood and urine routine, blood biochemistry, X-ray, CT, MRI, etc.) should be performed to make a comprehensive analysis for accurate diagnosis and favorable treatment.