ObjectiveTo evaluate the efficacy and safety of 1 940 nm thulium laser on peroral endoscopic myotomy （POEM） for treatment of patients with achalasia of cardia. MethodsFifteen patients undergoing POEM in Beijing Friendship Hospital from February 2016 to November 2016 were enrolled and divided into 1 940 nm thulium laser group （n=7） and high frequency electric knife group （n=8） using zelen′s design， with followed-up for three months. The operation time， success rate， efficacy， and complications were compared between the two groups. ResultsAll the procedures were successfully completed. There was no significant difference on baseline between the two groups （P＞0.05）. The time of total operation， creating submucosal tunnel， myotomy， and closing incision were not significantly different between the two groups （all P＞0.05）. The bleeding amount， creating tunnel bleeding amount， and myotomy bleeding amount were not significantly different between the two groups （all P＞0.05）. The complication rate during operation and one week after operation was not significantly different between the two groups （P=0.76）. The time of creating mucosal incision for the 1 940 nm thulium laser group was longer than that of the high frequency electric knife group（3.7±3.0 min VS 2.3±1.3 min， P=0.02）. After one month of follow-up， the efficiency of the 1 940 nm thulium laser group and the high frequency electric knife group was 100.0％ （7／7） and 87.5％ （7／8）， respectively （P=0.33）， and the complication rate was 14.3％ （1／7） and 12.5％ （1／8）， respectively （P=0.92）. After three months of follow-up， the efficiency of the two groups was 100.0％ （7／7） and 75.0％ （6／8）， respectively （P=0.16）， and the complication rate was 28.6％ （2／7） and 12.5％ （1／8）， respectively （P=0.60）. Conclusion1 940 nm thulium laser and high frequency electric knife both have good utility on POEM. 1 940 nm thulium laser decreases the operating time and bleeding compared with high frequency electric knife.