Objective To study the value of perioperative application of geriatric nutritional risk index (GNRI) in elderly patients with gastrointestinal tumor. Methods GNRI or nutritional risk screening 2002 (NRS 2002) was used to eva-luate the nutritional risk in elderly patients (≥60 years old) with gastrointestinal tumor surgery. Both operative complications and postoperative hospital stay in elderly patients with geriatric nutritional risk or nutritional risk were compared with those without geriatric nutritional risk or nutritional risk. The effect of preoperative nutritional support on operative complications and postoperative hospital stay in two groups was studied. Results A total of 150 elderly patients were enrolled. Geriatric nutritional risk and nutritional risk in the patients was predicted at 60.00%(90/150) and 40.67%(61/150) respectively. The Kappa value was 0.062 (P=0.415). Operative complication rate in the patients with geriatric nutritional risk was 13.33% (12/90) and postoperative hospital stay (10.37±4.66) days without significant difference (P>0.05) when compared with those [23.33% (14/60), (11.80±6.36) days] in the patients without geriatric nutritional risk. Preoperative nutritional support decreased operative complications 6.38% (3/47) and length of postoperative stay (8.85±2.58) days in geriatric nutritional risk patients compared with those [20.93% (9/43), (12.02±5.78) days] without preoperative nutritional support (P<0.05). No significant difference was present between operative complications [13.11% (8/61)] and length of postoperative stay [(10.56±4.58) days] in the patients with nutritional risk and [20.22% (18/89), (11.20±5.95) days] in the patients without nutritional risk (P>0.05), and between [10.26% (4/39), (10.03±4.94) days] in nutritional risk patients with preoperative nutritional support and [18.19% (4/22), (11.50±3.78) days] in those without preoperative nutritional support (P>0.05). Conclusion GNRI could be used to screen the nutritional risk of the patients with gastrointestinal tumors before operation, and used as a reference for preoperative nutritional support.