Objective To investigate the anatomical character and variation of non-recurrent laryngeal nerve （NRLN）， and to explore measurement to identify and prevent injury of this nerve during thyroidectomy. Methods Clinical data of 2 211 patients who underwent thyroidectomy from Jan. 2007 to Jun. 2012 in Peking Union Medical College Hospital were analyzed retrospectively， and 114 patients with NRLN of related literature reviews were analyzed too. Results There were 3 479 recurrent laryngeal nerve （2 211 cases） which were exposed during thyroid operation in Peking Union Medical College Hospital， of which 11 cases were confirmed to be right NRLN （0.32%， 11/3 479）. Of the 11 cases， 3 cases were typeⅠ， 7 cases were typeⅡA， and 1 case was typeⅡB， one case was also found to have a recurrent branch. None of them injured during operation. One hundred and fourteen cases of NRLN （0.14%-4%） were found in literature reviews. Of the 114 cases， 109 cases were confirmed to be right NRLN， of which 4 cases were typeⅠ （3.7%， 4/109）， 75 cases were typeⅡA （68.8%， 75/109）， 9 cases were typeⅡB （8.3%， 9/109）， 21 cases were unclear （19.3%， 21/109）， 3 cases were also found to have a recurrent branch （2.8%，3/109）. Five cases were confirmed to be left NRLN， of which 2 cases were typeⅡA， 3 cases were unclear， 1 case was also found to have a recurrent branch. Of all the 104 cases reported by treatises and case reports， 16 cases injured during operation， of which 1 case was typeⅠ， 9 cases were typeⅡA， 6 cases were unclear. Conclusions NRLN， which is a rare anomaly， usually happens on the right， and very vulnerable during thyroid surgery. The most usually injured type is typeⅡA. Fully acknowledgment of the NRLN and its variant types is very helpful to avoid damage during thyroid surgery.