Abstract: Objective To identify the factors that affect the safety and efficacy of peroral endoscopic myotomy (POEM) for treatment of achalasia. Methods Data of consecutive patients undergoing POEM for confirmed achalasia between December, 2010 and December, 2015 were collected, including the procedure time, approach of tunnel entry incision, approach of myotomy, complications and follow-up data. Results Among the total of 439 patients enrolled, the overall complication rate was 28.7% (126/439). Treatment success (Eckardt score≤3) was achieved in 94.5% of 364 patients followed up for a median of 6 months (1-48 months), and the mean score was reduced significantly from 6.7 ± 1.5 before treatment to 1.2 ± 1.1 after the treatment (P<0.05). Logistic regression revealed that the year when POEM was performed and the approach of entry incision were two significant factors contributing to complications: with the year 2015 as the reference, the odds ratio (OR) was 9.454 (95% CI: 2.499-35.76) for the years before 2011, 2.177 (95% CI: 0.794-5.974) for 2012, 3.975 (95% CI: 1.904-8.298) for 2013, and 1.079 (95% CI: 0.601-1.940) for 2014; with the longitudinal entry incision as the reference, the OR was 0.369 (95% CI: 0.165-0.824) for inverted T entry incision and 0.456 (95%CI: 0.242-0.859) for transverse entry incision. The approach of myotomy was the significantly associated with symptomatic relapse: with full-thickness myotomy combined with indwelling an anti-reflux belt as the reference, the OR was 0.363 (95% CI: 0.059-2.250) for gradual full-thickness myotomy, 2.137 (95% CI: 0.440-10.378) for circular muscle myotomy, and 4.385 (95% CI: 0.820-23.438) for circular muscle myotomy in combination with balloon shaping; the recurrence rate was 0 with a full-thickness myotomy. Conclusion The complication rates of POEM appears to decrease over time, and an inverted T entry incision is the best choice for controlling the complications. Gradual full-thickness myotomy is an excellent approach for treatment of achalasia in terms of the relapse rate, procedure time and the incidence of reflux esophagitis.