Background The surgical approach for patients with Siewert type II AEG remains controversial. Several studies have described a new laparoscopic radical resection approach of Siewert type II AEG through the left diaphragm. However, the technical safety and feasibility of the new surgical approach compared with the transhiatal approach have not yet been tested. Study design We retrospectively reviewed patients with AEG who underwent TSLG and LTH operations in the Guangdong Provincial Hospital of Chinese Medicine between January 2017 and April 2021. Histologically confirmed AEG and D2 lymphadenectomy with curative R0 patients were included, and patients with Siewert I/III AEG or distant metastasis were excluded. Blood loss, the amount of harvested lymph node, and complications related to surgery were evaluated. Results A total of 99 patients with Siewert type II AEG were analyzed, 44 in the TSLG group and 55 in the LTH group. There was no difference in clinicopathological features between the two groups. The more harvested lymph node (23.33 +/- 11.41 vs. 32.18 +/- 12.85, p < 0.01), lower mediastinal lymph node (1.07 +/- 2.08 vs. 3.25 +/- 3.31, p < 0.01), and longer proximal margin length (3.08 +/- 1.19 vs. 4.47 +/- 0.95 cm, p < 0.01) were observed in the TSLG group. The rate of cure (R0 gastrectomy) in the TSLG group was higher than that in the LTH group (100% vs. 89.09%, p = 0.03). Conclusion The TSLG approach is associated with improved surgical views, simplified lymphatic dissection in the inferior mediastinum, and more reliable margins. TSLG surgery may be an effective addition to LTH surgery, particularly when lower mediastinal lymph node metastases are suspected.