In the ICU,nutritional status is intimately related to the prognosis of critically ill patients and cannot be neglected;nonetheless,between 38%～78%of critically ill patients are malnourished.Individualized nutritional monitoring and therapy is recommended for critically ill patients to improve prognosis.Nutritional treatment includes enteral and parenteral nutrition.Enteral nutrition can be provided by prepyloric feeding through a nasogastric tube,which is simple and generally applicable,or by retropyloric feeding through a nasojejunal tube,which can reduce the risk of reflux aspiration.Parenteral feeding can be administered by creating peripheral venous access for convenient administration or central venous access for the delivery of nutritional solutions with high osmotic pressure.In addition to the patient's condition,the choice of nutrition route should take into account the initiation time,ability to meet nutritional needs,and potential feeding related complications.Current guidelines are not united,and previ-ous research has not fully addressed existing conflicts.In this paper,problems associated with each nutrition pathway are reviewed to provide a clinical reference.