1. External ear lesions: cerumen embolism, foreign bodies, boils and tumors in the external ear canal; 2. Middle ear lesions: eustachian tube lesions, acute and chronic otitis media, tumors, etc., also seen with tympanic chamber sclerosis and vascular lesions in the tympanic chamber; 3. Inner ear lesions: Meniere’s disease, sudden deafness, otosclerosis, ototoxic drugs, noise, inner ear damage due to infection, etc. 4. Postcochlear auditory system lesions: such as auditory neuroma, pontine horn lesions, etc. Other systemic lesions: hypothyroidism, diabetes and inner ear concussion caused by head trauma, etc.; 6. Unknown causes: Most tinnitus patients cannot find a clear cause.