Abstract: Objective To evaluate the safety and effectiveness of magnesium sulphate for reducing the incidence of the emergence agitation in patients undergoing surgery for esophageal carcinoma with general anesthesia. Methods This randomized, double-blind, controlled clinical trial was conducted in patients undergoing elective radical resection of esophageal carcinoma in Sichuan Provincial People’s Hospital between October, 2015 and March, 2016. The patients underwent surgeries under general intravenous anesthesia, and after anesthesia induction, the patients were infused with magnesium sulphate at the rate of 0.1 mL·kg-1·h-1 (2.5 g magnesium sulphate in 50 ml saline pumped at 5 mg·kg-1·h-1) or saline (control group) at the same speed until the end of the surgery. The Riker’s sedation agitation scale, pain score, muscle tension score, extubation time, residence time in the postanesthesia care unit (PACU), and adverse reactions were recorded. Results A total of 108 patients were enrolled including 57 in magnesium sulphate group and 51 in the control group. Riker’s sedation agitation scale in the PACU, pain score, and muscle tension score were all significantly lower but the extubation time was longer in magnesium sulphate group than in the control group (P<0.05). In all the patients, blood Ca2 + level was reduced significantly after the operation; blood Mg2 + level was significantly lowered postoperatively in the control group, and the postoperative Mg2+ level was significantly higher in magnesium sulphate group than in the control group (P<0.05). Mg2+ level underwent no significant variations in magnesium sulphate group after the operation (P>0.05). The residence time in the PACU, postoperative Riker’s sedation agitation scale score, and blood K+ level were all similar between the two groups(P>0.05). Conclusion Infusion of magnesium sulphate at 5 mg·kg-1 ·h-1 can significantly reduce the incidence of emergence agitation in patients undergoing esophageal carcinoma under general anesthesia without causing such complications such as muscle recovery delay or electrolyte disorder.