Objective: To investigate the feasibility and safety of implementing modified tubular gastric side-overlap anastomosis in laparoscopic proximal gastrectomy. Methods: In this retrospective, descriptive case series, we analyzed clinical data of seven patients who had undergone laparoscopic proximal gastrectomy and gastrointestinal reconstruction with modified tubular gastric side-overlap anastomosis from October 2022 to March 2023 in the Second Affiliated Hospital of Fujian Medical University. The study patients comprised five men and two women aged 57-72 years and of body mass index 18.5-25.7 kg/m2. All seven patients had preoperative gastroscopic and pathological evidence of esophagogastric junction cancer and all were found by preoperative enhanced computed tomography and/or endoscopic ultrasonography to have stage CT1-2N0M0 tumors. The main steps in the reconstruction of a modified tubular gastric side-overlap anastomosis are as follows: (1) mobilizing the lower esophagus and opening the left pleura to expand the space; (2) severing the esophagus with a linear cutter stapler; (3) creating a 3-cm-wide tubular stomach along the greater curvature; (4) creating a 5-cm guide line on the lesser curvature of the anterior wall of the tubular stomach and a small opening below the guide line; (5) rotating the esophageal stump 90° counterclockwise and making a small opening on the right posterior wall of the esophageal stump, along with using a 45-mm linear cutter stapler for esophagogastric side-to-side anastomosis under the guidance of the gastric tube and guide line ; (6) closing the common opening using barbed sutures; (7) embedding the cut edge of the esophageal stump such as to closely oppose it to the esophagus; (8) using barbed sutures to continuously suture the lower esophagus bilaterally to the anterior wall of the tubular stomach; and (9) closing the opened esophageal hiatus and pleura. The main outcome measures were intraoperative (operation time, digestive tract reconstruction time, closing the common opening time, intraoperative blood loss, and number of dissected lymph nodes), postoperative (time to passage of flatus , time to liquid diet, time to ambulation, length of postoperative hospital stay, and postoperative complications), pathological (maximum diameter of the tumor and pathological stage) and findings on follow-up. Results: Laparoscopic proximal gastrectomy with reconstruction of a modified tubular gastric side-overlap anastomosis was successfully completed in all seven patients; no conversion to laparotomy was required and there were no postoperative complications. The operation time, digestive tract reconstruction time, and closing of common opening time were 187-229, 61-79, and 7-9 minutes, respectively. Intraoperative blood loss was 15-23 ml and the number of dissected lymph nodes was 14-46 per case. Time to passage of flatus, time to liquid diet, time to ambulation, and postoperative hospital stay were 1-2, 2-3, 3-4, and 6-7 days, respectively. Postoperative pathological examination showed that the maximum tumor diameters were 1.6-3.3 cm in four patients with stage IA disease and three patients with stage IB. The seven patients were followed up for 6-11 months, during which none required routine use of proton pump inhibitors or gastric mucosal protective agents and there were no deaths or tumor recurrence/metastasis. No patients had anemia or hypoproteinemia 3 and 6 months after surgery. Six months after surgery, NRS2002 and GERDQ scores were 1-2 and 2-3, respectively. Gastroscopy showed narrow anastomoses in 6 patients with Los Angeles grade A and one patient with grade B disease. No evidence of significant bile reflux was found and no anastomotic stenosis or reflux was detected on upper gastrointestinal angiography. Conclusion: It is safe and feasible to implement modified tubular gastric side-overlap anastomosis for digestive tract reconstruction in laparoscopic proximal gastrectomy.