Objective To evaluate the efficacy and safety of peroral endoscopic myotomy (POEM) in achalasia of cardia (AC) patients with the long course. Methods A total of 159 AC patients who received POEM from January 2015 to March 2022 in the First Affiliated Hospital of Soochow University were divided into the long course group (≥10 years) and the non-long course group (<10 years). The baseline information, POEM procedure and postoperative recurrence were compared and the differences between the recurrent patients and non-recurrent patients in the long course group were explored. Results The age (57.09±14.30 years VS 42.08±15.68 years, t=5.569, P<0.001), the rate of treatment history [28.9% (13/45) VS 9.6% (11/114), χ2=9.319, P=0.020], the proportion of Henderson grade Ⅲ esophagus [17.8% (8/45) VS 6.1% (7/114), χ2=7.020, P=0.030] in the long course group were significantly higher than those in the non-long course group. The recurrence rate in the long course group was significantly higher than that in the non-long course group [33.3% (15/45) VS 14.9% (17/114), χ2=6.811, P=0.009]. In the long course group, the age (62.50 ± 16.94 years VS 53.77 ± 12.95 years, t=-2.121, P=0.040), and the rate of treatment history [53.3% (8/15) VS 16.7% (5/30), χ2=6.544, P=0.016] in the recurrent patients were higher than those in the non-recurrent patients. Conclusion POEM is safe and effective for long-course AC patients. In patients with the long course, the aged patients with previous treatment are more likely to relapse.