With the development of medical technology and the improvement of living standards, the proportion of senior citizens continues to rise, and China is gradually moving into an aging society. Compared with younger patients, older patients are more likely to have chronic diseases, such as hypertension, diabetes, and chronic bronchitis, and have poorer cardiopulmonary reserve, making it more difficult for them to withstand surgery and postoperative complications. Therefore, they may receive more examinations and laboratory tests before and after surgery. The only way for patients and their families to better cooperate with the completion of preoperative examinations and perioperative care is to truly understand the physical function characteristics of elderly patients. 1. Cardiovascular The leading cause of postoperative death in patients over 80 years of age is myocardial infarction, and more than half of postoperative complications or postoperative deaths are related to the cardiovascular system. One of the reasons for this is that cardiovascular system disease is very common in the elderly. Intimal hyperplasia of coronary vessels is significantly associated with age, while increasing age affects the cardiac conduction system, and arrhythmias are a common postoperative complication (especially in thoracic surgery). The persistent reduction of cardiomyocytes in the right and left ventricles as well as the compensatory increase in volume will cause abnormalities in the blood supply function of the heart. Therefore, for most elderly people, preoperative echocardiography and electrocardiography may be routinely performed, mainly to assess cardiac reserve function and to prevent cardiac insufficiency or failure in the perioperative period. 2. Respiratory As increasing age will have an impact on respiratory muscles, ventilatory function, and pulmonary vasculature, elderly patients are often associated with reduced respiratory reserve function. Decreased diaphragmatic strength, calcification of intercostal cartilage and atrophy of intercostal muscles will cause a decrease in respiratory strength, and the lung surface area available for gas exchange will be reduced by 15% in patients aged 70 years. At the same time, the body’s ability to absorb oxygen decreases with increasing age. In addition, the weakened nerve reflexes of the elderly make patients with poor respiratory function more prone to misaspiration, further increasing the risk of pulmonary atelectasis and postoperative pulmonary infection in elderly patients. 3. Renal function After the age of 50, the number of kidney units decreases, and by the age of 70, more than half of the kidney units will be gone. Therefore, compared with younger patients, older patients are more likely to have abnormal renal function, electrolyte disorders and acid-base imbalance. At the same time, the reserve function of renal filtration is also reduced in elderly patients, resulting in a weakened ability to concentrate urine, which is more susceptible to ischemia or nephrotoxic substances, which in turn causes renal failure. Therefore, clinically, during the perioperative period, doctors may pay great attention to the urine volume of elderly patients to try to avoid impaired renal function. 4. Gastrointestinal function The peristalsis of the gastrointestinal tract will gradually weaken with age, and its coordination is also poorer than that of young people, so it is more likely to cause swallowing difficulties and misaspiration after surgery. In terms of nutrient absorption, the villi of the small intestine are shortened in patients over 60 years of age, which leads to a decrease in the surface area for nutrient absorption. Therefore, the risk of malnutrition is very high in elderly patients with tumor and surgically induced hypermetabolic state. In addition, the liver function decreases after the age of 50, and the ability to synthesize nutrients and metabolize toxins decreases accordingly, making malnutrition and other problems more likely to occur after surgery. The advent of an aging society is unstoppable, and the only way to better understand the risks of treatment and avoid them is to carefully understand the characteristics of the body functions of the elderly, whether it is the patients themselves or their families, or the doctors or caregivers. We believe that with the continuous development of minimally invasive treatment methods and the spread of the concept of individualized and comprehensive treatment, we will be able to bring more suitable treatment and care to more elderly people.