Decreased sound tolerance includes hyperacusis and/or misphobia (phonophobia). As a commonly subjective symptom, tinnitus is defined to be a sound perceived in the ear or head without corresponding sound or electrical stimulus in the surrounding environment. It is usually occurred with or without hearing loss or harmful psychic reaction, which includes dyssomnia, annoy, rage, anxiety, depress, hard to concentrate, etc. Frequently, tinnitus is accompanied by decreased sound tolerance, while this text is aimed to review the correlated concepts of decreased sound tolerance,and focus on the hyperacusis which is a more common symptom.