One ear may be blocked due to cerumen impaction, secretory otitis media and sudden deafness. 1. Cerumen impaction: excessive secretion of cerumen in one ear and obstruction of cerumen discharge will block the ear, which may cause one ear to look like it is blocked, and it can be restored to normal after the cerumen is cleaned out. 2. Secretory otitis media: It may be related to infection, pharyngeal reflux, Eustachian tube pharyngeal orifice blockage and other factors, which may cause fluid accumulation in the middle ear, resulting in occlusion of one ear, which feels like blockage, and may be accompanied by hearing loss, tinnitus, earache and other symptoms. 3. Sudden deafness: it may be related to the inner ear blood supply obstacle, membrane labyrinth accumulation of water and other factors, can suddenly attack, it will feel like the ear is blocked, may also be accompanied by tinnitus, hearing loss and other symptoms. One side of the ear like being blocked, it is recommended to consult a doctor for examination and standardized treatment after a clear diagnosis, to avoid delaying the condition.