As society progresses, the average life expectancy of people is gradually increasing. The proportion of elderly patients among hospitalized patients is increasing. The physiological and pathological characteristics of elderly patients have their special characteristics compared with those of young people. The main principles of nutritional support for elderly patients should be grasped as follows: 1. Early correction of hypovolemia, acidosis, low sodium, low potassium and other water-electrolyte and acid-base balance disorders. 2.According to age, body mass index, whether fasting, primary disease, different courses of the same disease, drainage and whether other cardiac, pulmonary and renal diseases are accompanied, choose the suitable nutrition support route, appropriate amount of calories and nutrients, and formulate individualized nutrition support program. 3.As long as the patient’s gastrointestinal function still exists, enteral nutrition is preferred. 4.Progressively correct malnutrition in elderly patients by giving half of the required nutrition first, and then gradually increasing to the full amount. Elderly patients undergoing emergency surgery should not be treated with nutritional support before surgery.