Colorectal cancer is one of the most common tumors and patients with colorectal cancer often suffer from malnutrition and weight loss. Affected by reduced intake intestinal obstruction and malabsorption malnutrition is more common in colorectal cancer patients than in non - gastrointestinal tumor patients. Patients with colorectal cancer should undergo nutritional risk screening 2002 NRS 2002 and patient-generated subjective globe assessment PG-SGA . The European Society for Parenteral and Enteral Nutrition ESPEN strongly recommends enhanced recovery after surgery ERAS for all tumor patients undergoing radical or palliative surgery. ERAS can reduce the incidence of complications after colorectal surgery promote rehabilitation and shorten hospital stay. In the ERAS protocol ESPEN recommends that every patient should be screened for nutritional risk and if there is nutritional risk additional nutritional support should be given for patients with severe malnutrition nutritional intervention should be carried out for at least 10-14 days before operation even at the cost of delaying operation. Different surgical methods will have different effects on the incidence of postoperative complications mortality and 3-year long-term survival rate of colorectal cancer patients. Clinicians should pay attention to the nutritional status of patients after discharge reasonably carry out nutritional intervention and follow the patients with nutritional risk at discharge in a planned way.