Objective To investigate the efficacy and value of intra-operative neuromonitoring (IONM) in preventing,identifying and repairing recurrent laryngeal nerve injury (RLNI) during thyroidectomy and parathyroidectomy.Methods Data were collected from a series (n =351) of patients operated in our department between Jan 2015 and Dec 2017.Results With IONM navigation a total of 460 recurrent laryngeal nerves were identified during surgery.Anatomic variations were found in 6 cases,3 were non-recurrent laryngeal nerve.Others were morphological branching variation.There were 4 cases of temporary RLNI,all were unilateral.Total temporary RLNI rate was 1.1％.All 4 cases recovered completely in 3 months after surgery.Complete transection injury of RLN were found in 2 cases,one underwent immediate nerve anastomosis,with the voice significantly improved in 6 months.The total permanent RLNI rate was 0.5％.There was no hoarseness after operation in patients with normal IONM signal.The incidence of vocal cord paralysis was 57.14％ in patients with loss of IONM signal but normal appearance of RLN.Use of IONM did not increase operation time.Conclusions IONM had significant advantages in recognition of RLN,repair of intraoperative RLNI and prediction of postoperative voice condition,which could improve the safety of surgery.