Objective To explore the effect of intraoperative mild hyperventilation on postoperative shoulder pain(PLSP)in patients undergoing gynecological laparoscopic surgery.Methods Eighty-two pa-tients,aged 18-64 years,BMI 18.5-32.0 kg/m2,ASA physical status Ⅰ or Ⅱ,who underwent gyneco-logical laparoscopic surgery from January to September 2023 were selected.According to the random number table method,the patients were divided into two groups:observation group and control group,41 patients in each group.The observation group was given mild hyperventilation during the operation to maintain PETCO230-33 mmHg,and the control group was treated with conventional mechanical ventilation to maintain PETCO2 35-40 mmHg.The incidence of PLSP and VAS pain score of PLSP were recorded 12,24,48,72 hours,and 1 week after operation.The results of arterial blood gas analysis were recorded before anesthesia induction,15 minutes after pneumoperitoneum,at the end of operation,and 24 hours after operation.The intraoperative consumption of propofol and remifentanil,extubation time,bradycardia(HR＜50 beats/mi-nute),and intraoperative hypotension(SBP＜90 mmHg)were recorded.The occurrence of adverse reac-tions such as nausea and vomiting within 72 hours after operation and the requirement for rescue analgesia within 1 week after operation were recorded.Results Compared with the control group,the incidence of PLSP and VAS pain scores 12,24,48,72 hours,and 1 week after operation in the observation group were significantly reduced(P＜0.05),and PaCO2 15 minutes after pneumoperitoneum and at the end of opera-tion were significantly reduced(P＜0.05).There were no significant differences between the two groups in intraoperative consumption of propofol and remifentanil,extubation time,incidence of intraoperative brady-cardia and hypotension,incidence of nausea and vomiting within 72 hours after surgery,and requirement for rescue analgesia within 1 week after surgery.Conclusion Mild hyperventilation in gynecological laparo-scopic surgery can effectively reduce the incidence of PLSP and the degree of pain within 1 week after sur-gery,and does not increase the related adverse reactions within 72 hours after surgery.