The cause of unilateral tinnitus in the left ear may be related to external ear canal factors, middle ear factors, inner ear factors, etc., which need to be further differentiated and diagnosed by the doctor. 1. External ear canal factors: cerumen impaction, foreign bodies in the ear canal, otitis externa, etc. can cause blockage of the external ear canal, resulting in unilateral tinnitus in the left ear. 2. Middle ear factors: such as secretory otitis media and other middle ear pathologies, can lead to tinnitus in the left ear. 3. Inner ear factors: such as inner ear auditory nerve damage, left sudden deafness, acoustic neuroma can also lead to unilateral tinnitus in the left ear. It is recommended that people with unilateral tinnitus in the left ear should go to the hospital in time to clarify the cause of the disease and carry out standardized treatment under the guidance of the doctor, so as to avoid the delay of the disease and bring adverse effects to the body.