Most of the obese patients are accompanied by various obesity-related diseases, and the common diabetes, hyperlipidemia and hypertension have become the “necessary” diseases of obesity. It is also because of the complexity of the physical condition of the patient treated by bariatric surgery that more tests are performed before the surgery, which is also responsible for the life and health of the patient. In order to achieve better surgical results, a comprehensive understanding of the patient’s health includes blood glucose, blood lipids, blood pressure control and nutritional status, as well as disease history, diet and exercise, cardiopulmonary function, assessment of insulin function, and a series of other physical examinations, through which the findings are used to develop the most reasonable and perfect treatment plan for the patient. There are many different types of bariatric surgery, and the preoperative examination is also to come up with the best plan to choose the most suitable surgery for the patient, which can reduce the risk of surgery, reduce the occurrence of related complications, and improve the safety of surgery. In addition to the above-mentioned routine tests, there are some special tests for patients who need special tests. For example, 24-hour urine protein tests are required for patients with a history of diabetes mellitus <10 years but combined with diabetic retinopathy and positive urine microprotein. Women of childbearing age are checked for urine pregnancy tests. A history of esophageal disease and peptic ulcer disease requires gastroscopy. Those who are >60 years old and have a history of long-term smoking and chronic lung damage need to have a pulmonary function test. This series of physical examination process before surgery is tedious, but it is our responsibility to our patients and the rigor of our medical treatment.