Objective To evaluate the effect of mediastinal drainage tube placed in the left thoracic cavity after partial resection of the mediastinum pleura in robot-assisted McKeown esophagectomy for esophageal carcinoma, and to compare it with the traditional method of mediastinal drainage tube placed in mediastinum. MethodsWe retrospectively analyzed clinical data of 96 patients who underwent robot-assisted McKeown esophagectomy for esophageal carcinoma by the surgeons in the same medical group in our department between July 2018 and March 2021. There were 78 males and 18 females, aged 52-79 years. Left mediastinum pleura around the carcinoma during operation was resected in all patients. Patients were divided into two groups according to the method of mediastinal drainage tube placement: a control group (placed in mediastinum) and an observation group (placed through the mediastinal pleura into the left thoracic cavity with several side ports distributed in the mediastinum). The incidence of left thoracentesis or catheterization after surgery, anastomotic fistula and anastomotic healing time, other complications such as pneumonia and postoperative pain score were also compared between the two groups. Results There was no statistical difference in baseline data or surgical parameters between the two groups. The percentage of patients in the observation group who needed re-thoracentesis or re-catheterization postoperatively due to massive pleural effusion in the left thoracic cavity was significantly lower than that in the control group (5.6% vs. 21.4%, P=0.020). The incidence of anastomotic leakage (3.7% vs. 7.1%, P=0.651) and the healing time of anastomosis (18.56±4.27 d vs. 24.33±5.48 d, P=0.304) were not statistically different between the two groups, and there was no statistical difference in other complications such as pulmonary infection. Moreover, the postoperative pain score was also similar between the two groups. Conclusion For patients whose mediastinal pleura is removed partially during robot-assisted McKeown esophagectomy for esophageal carcinoma, placing the drainage tube through the mediastinal pleura into the left thoracic cavity can reduce the risk of left-side thoracentesis or catheterization, which may promote the postoperative recovery of patients.