Abstract: Objective:To explore the application effects of the harmonic scalpel in the reoperation of differentiated thyroid carcinoma.Methods:Fifty-two patients with differentiated thyroid carcinoma were treated with local section according to benign masses treatment method,and identified using pathological examination.The patients were randomly divided into the harmonic scalpel group(25 cases treated with harmonic scalpel) and conventional group(27 cases treated with traditional ligation method).All operations were performed by the same doctors.The total operation time,intraoperative bleeding,postoperative drainage and surgical complications(including postoperative bleeding,postoperative recurrent laryngeal nerve paralysis and postoperative hypoparathyroidism) between two groups were compared.The recurrence rate of residual cancer after half a year of operation was observed using the regular follow-up and reexamination,and the quality of life of patients after six months of surgery was assessed using the Karnofsky score.Results:The reoperation time,intraoperative bleeding and postoperative drainage in harmonic scalpel group were less than those in conventional group(P<0.01),and the quality of life in harmonic scalpel group after six months of surgery in harmonic scalpel group was significantly better than that in conventional group(P<0.01).The differences of the postoperative recurrent laryngeal nerve injury,incidence rates of transient and perpetual hypoparathyroidism,recurrence rate of residual cancer after half a year of operation and cost between two groups were not statistically significant(P>0.05).Conclusions:The effect of harmonic scalpel in the reoperation of differentiated thyroid carcinoma is better than that of traditional ligation method,which is worthy of promotion.