Abstract: Objective To evaluate the effect of intravenous administration of magnesium sulfate on improving the anesthesia effect in children undergoing laparoscopic surgery. Methods Eighty children undergoing elective laparoscopic surgery were randomly assigned into the observation （n = 40） and control groups （n = 40）. Prior to anesthesia induction, 40 mg/kg of magnesium sulfate was intravenously administered in the observation group, and an equivalent dose of normal saline was given in the control group. The same anesthesia induction and anesthesia maintenance regimes were adopted in two groups. The heart rate and mean blood pressure （MBP） were recorded in two groups at five time points： before induction （T0）, after intubation （T1）, after the establishment of the pneumoperitoneum （T2）, the end of surgery （T3）, after extubation （T4）, respectively. The incidence of postoperative adverse reactions including airway spasm, respiratory depression, nausea and vomiting and shivering, was recorded in two groups. The agitation and pain scores of the children were assessed after extubation （T4）, 30 min after extubation （T5） and 1 h after extubation （T6）, respectively. Results At T1 and T2, the MBP and heart rate in the observation group were significantly lower than those in the control group. At T4, the MBP in the observation group was considerably lower than that in the control group, and the hemodynamic fluctuation in the observation group was significantly smaller than that in the control group （all P < 0.05）. In the observation group, the agitation and pain scores at T4 and T5 were significantly lower compared with those in the control group （both P < 0.05）. Regarding the adverse reactions, the incidence of airway spasm in the observationb group was lower than that in the control group,but there was no significant difference between them（P > 0.05）. Conclusions Administration of 40 mg/kg of magnesium sulfate before anesthesia induction can stabilize intraoperative hemodynamics, mitigate postoperative pain, lower the incidence of agitation during the recovery period in children, and the incidence of postoperative airway complications was not increased.