If hoarseness persists for a long period of time after thyroid surgery, it may be due to damage to the recurrent laryngeal nerve on one side. The recurrent laryngeal nerve contains motor nerve fibers that innervate the vocal cords, and loss of the recurrent laryngeal nerve on one side may cause hoarseness. Although the healthy side of the vocal folds could be compensated for by over-adduction of the vocal folds to the diseased side, laryngoscopy showed that the diseased side of the vocal folds still could not be adducted, and therefore the original tone could not be restored. The recurrent laryngeal nerve runs in the sulcus between the trachea and the esophagus and passes between the branches of the inferior thyroid artery. Most laryngeal recurrent nerve injuries are caused by surgical treatment of the inferior pole of the thyroid gland, inadvertently cut the laryngeal recurrent nerve, ligature, or frustration pinch, pulling and causing permanent or temporary loss. Those caused by cutting, suturing are permanent or injury, while those caused by contusion pinching, pulling, hematoma compression are mostly temporary, and after timely treatment, they may recover gradually within 3-6 months. Due to the injury factors related to the recovery time, in order to avoid missing the best time to save, resulting in permanent damage, it is recommended that patients seek medical attention in a timely manner to identify the cause of the disease, to be appropriate treatment measures.