【Abstract】 Objective To explore the effects of intraoperative pumping of esketamine on the recovery outcome variables and postoperative pain in patients undergoing laparoscopic bariatric surgery. Methods Sixty-four obese patients undergoing elective laparoscopic bariatric surgery were randomly divided into control group or experimental group, with 32 patients in each group. In the experimental group, esketamine was pumped intraoperatively at the rate of 0.5 mg·kg-1·h-1 (concentration: 2.5 mg·ml-1, infusion rate i.e., 0.2 ml·kg-1·h-1). In the control group, equal volume of saline was pumped at the same rate. The time to extubation, spontaneous respiration, eye opening, modified Aldrete recovery 9 points(from discontinuation of remifentanil)，duration of PACU stay and incidence of adverse events during awakening were compared between the two groups. The visual Analogue Scale (VAS) method was used to record the patients' pain immediately after extubation, 6h postoperatively, 12h postoperatively and 24h postoperatively. The changes in heart rate and blood pressure before anesthesia (T0), 5 minutes after induction of anesthesia (T1), 10 minutes (T2), 15 minutes (T3), 30 minutes (T4), immediately after extubation (T5), 5 minutes after extubation (T6), and the use of perioperative vasoactive drugs and antihypertensive drugs were recorded. Results The VAS values in the experimental group were lower than those of the control group at 6, 12 and 24 h after surgery, and the differences were statistically significant (P 0.05). There was no statistical difference between the two groups in the VAS scores immediately after extubation (P 0.05). There was no statistical difference in the recovery profile characteristics (P 0.05). The incidence of hypoxemia during the awakening period of anesthesia in the test group was lower than that in the control group, and the difference was statistically significant (P 0.05), and the incidence of other adverse reactions during the awakening period were not statistically different (P 0.05). At T1, there was a statistical difference in the mean arterial pressure between the two groups(P 0.05), and there was no statistical difference in the mean arterial pressure in the rest of the time period(P 0.05). The usage rate of phenylephrine in the test group was lower than that in the control group(P 0.05), and there was no statistical difference in the use of the other vasoactive drugs and antihypertensive drugs (P 0.05). Conclusion Intraoperative administration of esketamine has been shown to be an effective method for relieving acute postoperative pain, stabilizing hemodynamics, reducing the incidence of postoperative hypoxemia, and does not have a negative impact on the quality of postoperative awakening in patients.