Unilateral tinnitus may be an early sign of diseases such as sudden deafness, Meniere’s disease or acoustic neuroma, or it may be a symptom of other diseases. 1. Sudden deafness: the cause of this disease is not yet clear, may be related to viral infection, autoimmune and circulatory disorders and other factors. Patients often have unilateral hearing loss, tinnitus, vertigo and other manifestations. Tinnitus may be the first symptom, so unilateral tinnitus may be an early sign of sudden deafness. 2. Meniere’s disease: it is an idiopathic inner ear disease, and its pathology is the accumulation of water in the membranous labyrinth. Patients often present with recurrent rotational vertigo, fluctuating hearing loss, tinnitus and a feeling of ear stuffiness. Tinnitus may be the earliest symptom of the disease, so unilateral tinnitus may be an early sign of sudden deafness. 3. Auditory neuroma: mainly refers to the tumor originated from the inner ear canal section of the VIIIth cerebral nerve. When the tumor size is small, it can often cause unilateral tinnitus, hearing loss and dizziness, and a few patients may have deafness for a longer period of time, so unilateral tinnitus may be an early sign of acoustic neuroma. Therefore, unilateral tinnitus may be an early sign of acoustic neuroma. When unilateral tinnitus occurs, it may also be caused by otitis media, eustachian tube dysfunction, etc. It is recommended to consult the doctor as soon as possible to find out the cause and treat it actively.