Objectives <p>Indocyanine green (ICG) can help surgeons identify the blood perfusion distribution of the gastric conduit. The aim of our study is to utilize ICG fluorescence for quantitative assessment of blood perfusion at the anastomotic site to minimize postoperative anastomotic leakage.</p> Methods <p>Patients who underwent McKeown esophagectomy with esophageal squamous cell carcinoma between August 1, 2019, and July 31, 2021, were enrolled in the study and randomly assigned to two groups. The intervention group received ICG fluorescence-guided anastomotic site selection. ICG fluorescence was used to quantitatively assess the blood perfusion fluorescence threshold at the anastomotic site in the gastric conduit, and anastomosis was performed only at sites where the fluorescence threshold exceeded the established threshold. In the control group, anastomosis was conducted at the visually evaluated site determined by the surgeon's experience.</p> Results <p>45 eligible patients were assigned to the intervention group, and 47 patients were allocated to the control group, respectively. Anastomotic leakage within 30&#xa0;days occurred in 6.7% (3/45) of the intervention group and in 21.3% (10/47) of the control group (p = 0.021). Additionally, no differences were observed in anastomotic stenosis within 90&#xa0;days, overall survival time or in the effect of neoadjuvant therapy on anastomotic leakage.</p> Conclusion <p>ICG fluorescence can identify the areas with good perfusion in the gastric conduit and significantly reduce the occurrence of anastomotic leakage following esophagectomy.</p> Trial Registration <p>ClinicalTrials.gov Identifier: NCT04229524.</p>