恶性肿瘤患者营养不良的发生率较高，其中以胃肠道肿瘤患者的营养不良程度为甚。胃肠道肿瘤除肿瘤自身消耗及特殊因子的释放，还经常因消化道的梗阻等症状，导致患者营养摄入不足或丢失过多，进一步加重患者营养不良程度。围手术期营养不良可增加患者术后相关并发症的发生率，延长住院时间，降低生活质量以及增加非计划性二次手术率，最终增加病死率。利用有效的营养筛查工具筛查出营养不良患者，在围手术期提供精准而有效的营养治疗，改善肿瘤患者营养状况，提高患者对抗肿瘤治疗的耐受性，降低不良反应和并发症的发生率，提高手术疗效，缩短住院时间，减少住院费用，从而改善患者临床结局，进而提高生活质量，延长生存时间。因此，胃肠道肿瘤患者围手术期营养筛查及精准营养治疗，对改善患者预后显得尤为重要。本文主要从胃肠道肿瘤患者发生营养不良的原因，营养状况的评估与筛查，精准营养治疗适应证，营养制剂的选择及使用途径等方面阐述目前的研究进展。

The incidence of malnutrition in patients with malignant tumors is high, especially in patients with gastrointestinal cancer. In addition to the consumption of tumor itself and the release of specific factors, gastrointestinal tumors are often caused by inadequate or excessive loss of nutritional intake due to obstruction of the digestive tract, which further aggravates the degree of malnutrition in the patients. Perioperative malnutrition can increase the incidence of postoperative complications, prolong hospital stay, reduce quality of life, increase unplanned second surgical rates, and ultimately increase mortality. By using of effective nutrition screening tool for scanning patients with malnutrition, providing accurate and effective nutritional support treatment in the perioperative period, improving the nutritional status of patients with tumor, it can improve the tolerance of patients with tumor, reduce the adverse reaction and complication rate, improve curative effect, shorten hospitalization time, reduce hospitalization costs, thereby improving the clinical outcome of patients, and improve the quality of life and prolong the survival time. Therefore, perioperative nutrition screening and accurate nutrition therapy for gastrointestinal cancer patients are of great importance to improve the prognosis of patients with gastrointestinal cancer. From the aspects of the causes of malnutrition in patients with gastrointestinal cancer, the assessment and screening of nutritional status, the precision nutrition therapy, and the choice and application of the nutritional preparations, this paper illustrates the current research progress.