Objective To investigate the efficacy and safety of gastric peroral endoscopic myotomy ( G-POEM) for postsurgical gastroparesis. Methods A retrospective analysis was performed on data of 47 patients with gastroparesis after subtotal gastrectomy, who underwent G-POEM at Zhongda Hospital Southeast University form August 2016 to June 2018. G-POEM procedure, complications related to G-POEM, and improvement of symptoms and gastric emptying function were observed. Results All patients underwent G-POEM successfully. No serious G-POEM-related complications were observed. During a follow-up period of 9. 8±5. 8 months (range 3-18 months), the scores of gastroparesis cardinal symptoms index (GCSI) were 1. 6±0. 5, 1. 2±0. 4, 1. 1±0. 6, 1. 4±0. 3 and 1. 7±0. 3 respectively at the 1st, 3rd, 6th, 12th, and 18th months after G-POEM, and all scores were lower than that before G-POEM (3. 8±1. 1, all P<0. 01). The results showed the symptoms of gastroparesis were improved significantly. Gastric emptying imaging showed the hemi-emptying time was 23. 8±8. 8 min, 21. 2±9. 5 min, 20. 9±8. 3 min and 26. 4±7. 8 min at the 1st, 6th, 12th and 18th months after G-POEM, respectively, significantly shorter than that before G-POEM (67. 8±12. 5 min, all P<0. 01). Three-dimensional ultrasonography results of gastric antrum volume showed that the hemi-emptying time was 26. 4 (21. 8, 40. 3) min, 22. 6 (13. 9, 32. 7) min, 24. 3 (18. 2, 36. 5) min and 26. 8 (16. 4, 38. 5) min at the 1st, 6th, 12th and 18th months after G-POEM, respectively, which were all significantly shorter than that before G-POEM [ 72. 5 ( 48. 3, 108. 6 ) min, all P<0. 01 ] . Conclusion G-POEM has a satisfactory long-term efficacy on the treatment of gastroparesis after subtotal gastrectomy with good safety.