Abstract： Objective To investigate the feasibility and safety of Proseal-laryngeal mask airway(PLMA) for anesthesia in endoscopic thyroidectomy.Methods Forty ASA class Ⅰ or Ⅱ patients underwent endoscopic thyroidectomy via breast approach were randomly divided into laryngeal mask venting group( Group P,n =20) and endotracheal tube venting group( Group T,n =20).Both groups were used the same anesthesia induction,maintenance and breathing parameter adjustment.The HR and MAP in both groups were recorded respectively before intubation,while intubation,2 min after intubation,before and after head back out center position,before extubation and 2 min after exbutation.The adverse effects of respiratory tract were recorded respectively.Results There were no significant changes in HR and MAP in Group P before and after intubation,as well as before and after extubation( all P ＞ 0.05 ) ;In Group T,the HR and MAP while intubation,2 min after intubation are higher than that before intubation (all P ＞ 0.05).The HR and MAP in Group T,2 min after exbutation are higher than before extubation(all P ＞ 0.05 ).The incidence rate of sore throat and hoarse postoperatively were lower in Group P than in Group T( all P ＞ 0.05 ).Conclusion PLMA could be safely and effectively used in the anesthesia of endoscopic thyroidectomy.