Objective: To investigate the effect of preoperative oral nutrition supplement (ONS) on the complication and perioperative nutritional status of the patients with esophageal cancer who had nutritional risk. Methods: A total of 60 patients with esophageal cancer with nutritional risk screening (NRS)2002≥3 who underwent surgery were randomly divided into the study and control groups. The study group received one week ONS (900 kcal/day of calories and 32 g/day of protein) before surgery and the control group received common semifluid diet only. The preoperative baseline data and postoperative indicators including postoperative complications, volume of drainage, time to exsufflation, albumin and blood transfusion, hospitalization duration and expense and the perioperative serum nutritional indicators (including levels of serum albumin, prealbumin, transferrin and retinol-binding protein before and 1, 3, 5, 7 d after surgery) were recorded. Results: Compared with the control group, the total complication rate (16.7% vs. 40.0%, P＜0.05) and the pulmonary complication rate (6.7% vs. 30.0%, P＜0.05) were significantly reduced in the study group. The perioperative albumin infusion ［(58.0±14.9) mL vs. (76.5±37.9) mL,P＜0.05］, postoperative hospitalization durations ［(15.7±4.3) d vs. (18.8±5.1) d, P＜0.05］ and total hospitalization time ［(22.7±5.7) d vs. (25.8±5.1) d, P＜0.05］ and expense ［￥(66 290.8±9 922.3) vs. ￥(72 491.8±12 535.1), P＜0.05］ were all significantly decreased in the study groups. The level of serum nutritional indicators including albumin, prealbumin, transferrin, retinol-binding protein fell significantly after operation, came to the deepest point on the 3th day after operation and gradually rose after that. However, they were still significantly lower than basal level on the 7th day. The prealbumin level of the study group on the 1th, 3th, 5th, and 7th day after operation were all significantly lower than those of the control group (P＜0.05), which was the same as to the retinol-binding protein except on the 5th day (P＜0.05). Conclusion: One week ONS before operation can effectively promote the nutritional status and postoperative rehabilitation of patients, reduce the incidence of postoperative complications, shorten hospital stay and decrease the expense.