Hoarseness is often the result of laryngeal pathology or dysfunction, but it is not uncommon for hoarseness to occur after surgery for thyroid disease. The association between thyroid surgery and hoarseness is not well understood. Hoarseness is a clinical manifestation of limited or fixed vocal fold activity, and the nerve that innervates vocal fold activity is medically known as the recurrent laryngeal nerve. The vast majority of hoarseness after thyroid surgery is due to damage to the recurrent laryngeal nerve during surgery, and less common causes include inflammatory swelling of the vocal cords caused by general anesthesia endotracheal intubation, abrasion of the vocal cords, arytenoid cartilage dislocation and other causes of postoperative vocal cord dyskinesia and hoarseness symptoms. Laryngeal recurrent nerve injury is the most serious complication of thyroid surgery, after laryngeal recurrent nerve injury patients usually have sequelae of vocal cord paralysis, will affect the quality of life of patients to varying degrees, bilateral laryngeal recurrent nerve injury in some patients need to early tracheotomy. Despite the rapid progress of modern medicine, the related knowledge and experience are getting richer and richer, and scholars are actively exploring the measures to reduce the injury of recurrent laryngeal nerve in thyroid surgery, but the injury of recurrent laryngeal nerve in thyroid surgery still occurs from time to time. Once hoarseness occurs after thyroid surgery, laryngoscopy should be performed to clarify the cause of hoarseness. If it is inflammatory swelling, vocal cord abrasion, can be given anti-inflammatory treatment and nebulized inhalation, usually one week after the hoarseness can be restored. If the arytenoid cartilage is dislocated, the arytenoid cartilage reset can be performed under surface anesthesia or general anesthesia with appropriate laryngeal forceps under supportive laryngoscopy, which is the most ideal treatment at present. As long as the arytenoid cartilage is accurately repositioned, the movement of the vocal folds will soon return to normal. If one repositioning fails, it can be repeated. If post-thyroid surgery hoarseness is caused by laryngeal recurrent nerve injury, a clinical distinction should be made between permanent and temporary. Temporary recurrent laryngeal nerve injury is often due to intraoperative laryngeal nerve clamping, excessive stretching, excessive dissection of the recurrent laryngeal nerve, resulting in nerve ischemia and edema. Temporary recurrent laryngeal nerve injury can be under the guidance of the doctor, given neurotrophic drugs, such as vitamin B1, B12 and other symptomatic treatment, usually within 3 months after the operation hoarseness can be restored. The most common reason for permanent recurrent laryngeal nerve injury caused by thyroid surgery is that the recurrent laryngeal nerve is inadvertently cut off during the operation or the recurrent laryngeal nerve is blindly ligated or stitched for hemostasis during the operation. Unfortunately, the majority of laryngeal recurrent nerve injuries during thyroid surgery are permanent laryngeal recurrent nerve palsy, with a smaller chance of temporary palsy. The traditional view on the treatment of recurrent laryngeal nerve injury complicated by thyroid surgery is to observe for 3-6 months before considering whether to take therapeutic measures, but more and more clinical studies have shown that recurrent laryngeal nerve injuries complicated by thyroid surgery should be treated with early surgical treatment in order to improve the rate of recovery of the function of the recurrent laryngeal nerve. There is no specific test to determine whether the recurrent laryngeal nerve has been ligated with sutures or severed, and recurrent laryngeal nerve exploration is the only way to determine the nature of the injury. Decompression of the recurrent laryngeal nerve is suitable for cases in which the recurrent laryngeal nerve is adhered by scar or ligated or sutured within 3 months after surgery, and the nerve function can be fully recovered after the scar is loosened and the suture is removed. In cases where the injury is more than 4 months old, although the hope of nerve function recovery decreases significantly with the removal of the wire knot, there are cases reported in the literature in which nerve function was recovered by laryngeal recurrent nerve decompression 6 months after the ligature was ligated or sutured in thyroid surgery. For early cases of unilateral laryngeal nerve severance, after laryngeal nerve exploration, according to the different conditions of laryngeal nerve injury, laryngeal nerve end-to-end anastomosis, cervical collateral laryngeal nerve anastomosis or neuromuscular grafting can be used to repair severed laryngeal nerves, and the tension and inward contraction of the vocal folds on the affected side can be restored, and the quality of vocalization can be improved. The laryngeal recurrent nerve injury complicated by thyroid surgery is mostly unilateral, and some patients may have bilateral laryngeal recurrent nerve injury due to simultaneous or sequential surgery of both lobes of the thyroid gland. Unilateral recurrent laryngeal nerve injury is only manifested as hoarseness, choking and coughing and vocal fatigue, and in some patients, about 6 months after the operation, due to the compensatory retraction of the contralateral vocal folds, the quality of their voice improved significantly, and the vocal fatigue, hoarseness, and choking and coughing were reduced significantly, and although it could not reach the condition before the injury, it could basically meet the needs of daily communication, and therefore most patients generally did not seek further treatment. However, there are still more patients in 6 months after the injury, the compensatory retraction of the contralateral vocal folds still can not effectively close the vocal folds, such as the injured side of the vocal folds outside the booth fixation, the vocal folds tension decline in the vocal folds flaccid, and the healthy side of the vocal folds are not at the same level, etc., hoarseness, vocal fatigue, and the performance of aspiration, choking and coughing, etc., are still very obvious. The treatment of patients with laryngeal recurrent nerve injury for more than 6 months is mainly aimed at promoting vocal fold closure, narrowing and eliminating vocal fold closure insufficiency. The main surgical procedures include type I thyroid chondroplasty, vocal cord injection, and arytenoid cartilage endoprosthesis. In the unfortunate event of bilateral laryngeal recurrent nerve injury, accompanied by obvious inspiratory dyspnea, laryngoscopy often shows that the bilateral vocal cords are more than paracentrally or medially fixed, and some patients often require emergency tracheotomy. For the late treatment of this group of patients, the main goal is not to improve vocal quality and malabsorption, but to widen the vocal folds, relieve dyspnea, remove the tracheal tube, and improve the quality of life. The main surgical procedures are arytenoid chondroplasty, vocal cord resection and vocal cord abduction. In conclusion, the most effective measure to eliminate laryngeal recurrent nerve injury during thyroid surgery is prevention, and the incidence of laryngeal recurrent nerve injury during thyroid surgery by experienced surgeons should not exceed 1. Studies have shown that exposure of the recurrent laryngeal nerve and protection of its trophic vessels throughout the whole process of thyroid surgery are effective in avoiding permanent damage to the recurrent laryngeal nerve. The author’s clinical experience of more than 4000 cases of thyroid surgery shows that the incidence of laryngeal nerve injury in thyroid surgery with full exposure of the recurrent laryngeal nerve is less than 1 per thousand, and in cases where the recurrent laryngeal nerve has been ligated or ligated within 3 months of thyroid surgery, laryngeal recurrent nerve decompression is performed, and the restoration of the function of the vocal cords can be up to 100 per cent.